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Excessive Engine Vibration at Idle

62K views 111 replies 25 participants last post by  75aces 
#1 ·
I have a '98 Corolla CE Automatic with 250k and am trying to figure out what is causing excessive engine vibration. The vibration happens mostly at 900 rpm and below, and is the worst while idling at stop lights (in drive with foot on brake). It is also noticeable while in neutral and park. If I am sitting at a long light I will often switch to neutral and push the gas pedal to get the rpms above 1000 (and thus stop the shaking). Its gotten steadily worse over the last year and at this point its so bad that I don't enjoy driving the car.

I took it to a mechanic and they said it was due to worn motor mounts. I had them replace the mounts (all 4) for a ridiculous price, but alas that did not fix the issue. In fact, the vibration feels worse with the new mounts! I took it back and the mechanic inspected it further, but said they couldn't find anything wrong and sent me on my way. After a bit of online research I have done the following:

• Replaced spark plugs with new OEM plugs
• Put in new air filter (OEM)
• Replaced PCV Valve and Grommet (OEM)
• Checked for loose hoses
• Replaced transmission fluid and filter (I realize this is probably unrelated, but it was due anyways)
• Inspected MAF Sensor (it looked clean to me)
• Inspected throttle body; it was slightly dirty but didn't seem that bad.

I also purchased some fuel injector cleaner, but haven't put it in yet (waiting until my tank is about empty as per instructions).

At this point I am not sure where to go from here. I've had 3 different mechanics inspect it and they all agree that the vibration is excessive, but none can find anything wrong! Suggestions? Also, please note that I am not very mechanically inclined and have a limited tool set. I can do basic stuff like switch out parts, etc.. but don't feel comfortable doing anything super technical.
 
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#5 ·
I was wondering about dirty injectors. That is why I got the fuel injector cleaner (as I mentioned in the original post). I didn't realize Seafoam could go in the gas tank, so I will look into it.

BTW; I gave the mechanic a bunch of grief for giving up on my issue and they decided to give it another shot with their best technician. Its in the shop now, so we will see what comes of that. :)
 
#3 ·
Check the bill from the engine mount job. Genuine toyota mounts are fluid filled and expensive just for the parts. If the mechanic used cheap aftermarket parts then thats what is likely wrong. Also did they replace the transmission mount? Its a beast to remove as you have to drop the subframe but see if they did 3 or 4 mounts and report back.
 
#6 ·
I did check the bill and they installed aftermarket parts (and marked them up a ridiculous amount). I confronted them about this and they claim that the parts they installed are just as good as the OEM mounts. They also said the OEM mounts for a 98 Corolla are not fluid filled (which the dealership confirmed), so theoretically the parts should be somewhat similar. And yes, they replaced all 4 mounts (including the transmission mount). When I brought it back to them they checked the mounts and said they looked to be working fine.
 
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#8 ·
I'll take a look. I am guessing this is something that I could check myself by crawling under the car with a flashlight? As I mentioned above, the car is back in the shop being inspected further, so perhaps the issue will be remedied when I get it back.. but if not I will definitely check out the exhaust system.
 
#10 ·
One last test before you throw out the towel. Have someone push on the front edge of the hood while you listen to the engine. If the rattle stops then you found the cause of your vibration(the hood).You need to adjust the 2 hood stay located on top of the radiator cross member. Turning them conterclockwise will tighten the hood and stop vibration.
 
#13 ·
Actually, yes; the hood does rattle. In fact, it makes a very loud rattling/squeaking sound when the car is shaking at low RPMs. Yesterday I added some cushioning to it that stopped the sound, but the engine still vibrates just as much. I didn't realize those "hood stay" could be adjusted, so I will go ahead and do that as well (thanks for that tip!).

So yes, adjusting the hood definitely helps with the annoying sounds, but doesn't address the engine vibration. If the car is running and the hood is open, I can visually look at the engine and see it vibrating excessively. In fact, if I watch while it warms up and the RPMs drop.. the engine goes from a minor vibration to a substantial shake.

Something I forgot to mention in the last post; the mechanic said that when they disconnected the transmission from the engine that the shake completely stopped, and something about when there isn't any load on the engine it is just fine.

-shawn
 
#11 ·
I still suspect the aftermarket mounts are too hard and not as good as genuine toyota mounts and thats the issue however considering all the free work they did diagnosing your car and the refund i really dont think you could ask for more from the shop. Sounds like an honest place to me. You could try contacting @ToyotaOfCoolSprings here on toyotanation in a private message. They give discounts and fair shipping to memebers on genuine parts could be the issue. Here are the part numbers you might want
12305-0d010 engine insulator rh
12371-0d020 engine insulator rear
12372-0d030 engine insulator lh
12361-0d021 engine insulator front
Please ensure you double check these part numbers before you order. Toyota of cool springs will ensure you get the right parts.
 
#14 ·
I still suspect the aftermarket mounts are too hard and not as good as genuine toyota mounts and thats the issue however considering all the free work they did diagnosing your car and the refund i really dont think you could ask for more from the shop.
You could be right, but the vibration was there before the new mounts and I'm fairly sure at this point that it wasn't completely due to the old mounts being bad. The mounts were bad for sure (well, 2 of them were at least), but I think they were actually cushioning the vibration a little instead of causing it. The mechanic actually said the same thing, and said it might take some time for the new mounts to soften up, which may decrease the vibration a little.

Getting new mounts just isn't an option at this point, and I am guessing it won't address the issue either. If the mounts were a little softer then the vibration might be a little less intense, but I suspect it would still be there. I also can't afford to switch out the mounts again. I don't have the skills (or tools) to do it myself, and even with discounted OEM parts, I doubt I could get it done for less than $600. I had originally called 5 different mechanics to get quotes and they all ranged between $950-$1300.

I can live with the vibration if need be, but my main concern has been that its a symptom of something else that needs to be fixed/replaced.
 
#12 ·
OP if you pursue this, there is one thing not mentioned that is meant to dampen engine vibrations.
The harmonic balancer that is part of the crankshaft pulley.
With 250k the rubber could well be deteriorated.

Regarding worn engine theory, if compression tests shown uneven cylinder contribution, vibration is probably there to stay.
 
#15 ·
How does one diagnose an issue with the harmonic balancer? Can I simply inspect the rubber for deterioration? And where exactly is this harmonic balancer at? :)

Unfortunately they didn't give me specific information/data on all the tests they performed. Since they were doing all the diagnosis for free, they didn't want to take the time to notate it all for me. However, I think I recall them saying that the compression tests indicated that everything was fine considering that its a 20yr old engine with 250k on it, but that if the same results were found on a newer engine that it might be a concern.
 
#18 ·
Great! Now that you adjusted the hood its time to do a simple test. You mentioned in your first post that you checked the vaccum hoses in case one was disconnected.As you know, a leak could be anywhere along the lines and not just at the connection. I would pinch them at several places and see if the engine stop vibrating. The first one that comes to mind and the easiest one to test is the brake booster hose.Test that one first and do the other lines afterward.Please report your findings.
 
#19 ·
You mentioned in your first post that you checked the vaccum hoses in case one was disconnected.As you know, a leak could be anywhere along the lines and not just at the connection. I would pinch them at several places and see if the engine stop vibrating. The first one that comes to mind and the easiest one to test is the brake booster hose.Test that one first and do the other lines afterward.Please report your findings.
As I said before, the mechanic said they checked for vacuum leaks and everything checked out. However, I will go ahead and try pinching the lines just for the heck of it. Where exactly is the brake booster hose? Still figuring out what everything under the hood is exactly.

Also, here is a link to a video I just took that shows the vibration. I put a glass of water in there to help show how strong it is. I am curious to know if people agree that the vibration is excessive after seeing the video! BTW; the camera is mounted on a tripod and is perfectly still, so any movement you see is from the engine.



Thanks,
Shawn
 
#21 ·
It does have A/C, but the vibration doesn't seem related. In fact, when I turn the A/C on it kicks the RPMs up higher (for example if its idling at 650, turning the A/C on will put it up to 800-900), which actually creates less vibration. I also don't run the A/C very often.

Its the first day without heavy rain for awhile, so I will mess around with my car some more and report back if I discover anything noteworthy.
 
#22 ·
Most similiar era cars when the idle is steady should have the idle drop down when you pull the dipstick, if it doesn't that could be a vacuum leak. Mine has a similiar problem, but my car is 18 years old with 100k and ive put 50K hard miles on it in the past few years. Needless to say many things are old and worn. I am thinking on top of everything else one amplifier to the problem is that everything is worn.

My car while parked has a lot of movement. I have nothing to compare too and don't know what a new 98 corolla should feel like. But pushing sideways at the front or rear of the car there is a lot of sideways movement. On mine the rear suspension, LF control arm and steering rods need attention.

My alternator is on its way out, if I hold both rear window switches up with the windows up the headlights dim excessively and the motor acts as if it has high load on it. While driving you can notice a power loss at times when doing that and you can hear the strain on the alternator.

Now all these things are not the golden answer but I assume all can play a roll in adding onto the existing problem. I have a lot of these parts waiting to go in the car so before I move on and end up chasing my tail I am going to knock out what I already have an see how it effects the car.

Once I know everything else is tightened up my first course of action would be to look into vacuum leaks, related gaskets, mounts, etc.
 
#23 ·
Most similar era cars when the idle is steady should have the idle drop down when you pull the dipstick, if it doesn't that could be a vacuum leak.
Ok, I tried doing that test. Engine was idling around 650-690 rpm (it jumps around randomly within that range), pulled the dipstick and nothing changed. Did it a few more times, and didn't seem to make any difference.
 
#25 ·
Does the vibration totally go away at any point, or just get less severe? Can you feel it cruising down the road at 60 miles an hour while the engine is turning a couple thousand RPM's? Have you noticed any engine performance drop off that might have coincided with the onset of the vibration?

I'm thinking it's a vacuum leak, but not a severe one, especially since you say the vibration lessens at higher RPM's. I would recommend getting a propane torch from the hardware store, you know, one of those little ones that are usually colored blue with the screw on head. DON'T light it, but open up the valve and, of course without hitting any moving parts, slowly work your way first around the intake manifold with the gas blowing and see if rpm's improve and/or the engine smooths out. If that doesn't have any affect, then trace every vacuum line back to whatever it is connected to and blow gas around those components as well.

Tell us what happens.

Chris
 
#28 ·
Does the vibration totally go away at any point, or just get less severe? Can you feel it cruising down the road at 60 miles an hour while the engine is turning a couple thousand RPM's? Have you noticed any engine performance drop off that might have coincided with the onset of the vibration?
It seems like the vibration pretty much goes away when I go above 1000 RPM. See the video that I just posted above. I did notice while doing that test that it vibrated a little bit for a couple seconds when I hit around 2000 rpm.. but otherwise it felt smooth. When I am cruising down the road there are so many other factors that its hard to tell. My car tends to shake from rough roads, old struts, and who knows what else.. it has all kinds of vibration/shaking/rattling beyond just the engine vibration thing, so unless I am going very slow or stopped, I can't really tell if its the engine or not.

I'm thinking it's a vacuum leak, but not a severe one, especially since you say the vibration lessens at higher RPM's. I would recommend getting a propane torch from the hardware store, you know, one of those little ones that are usually colored blue with the screw on head. DON'T light it, but open up the valve and, of course without hitting any moving parts, slowly work your way first around the intake manifold with the gas blowing and see if rpm's improve and/or the engine smooths out. If that doesn't have any affect, then trace every vacuum line back to whatever it is connected to and blow gas around those components as well.
I actually do have a propane torch already, but its a torch attachment that screws onto a Coleman propane camping gas bottle. I assume that would work as well? I will try out your test once the rain stops (if it ever stops.. this is Oregon after all). However, I'm not sure where all the vacuum lines are exactly. I'm still learning what everything under the hood is, and I haven't been able to find a clear chart or photos of what all the parts are. I guess I could just run propane over every everything I see under the hood! Haha :)
 
#26 ·
I'd suspect engine mounts too.

Vacuum is hard to find, but you can either use a spray bottle with water (the safest route), spraying about the engine bay to see if you can detect any change in vibration or hear a sucking sound, or use an unlit propane torch to do much of the same. The latter works better if you have a lean code and can watch fuel trims live as the engine idles.
 
#29 ·
Vacuum is hard to find, but you can either use a spray bottle with water (the safest route), spraying about the engine bay to see if you can detect any change in vibration or hear a sucking sound, or use an unlit propane torch to do much of the same. The latter works better if you have a lean code and can watch fuel trims live as the engine idles.
I'm going to try the propane thing. What is a lean code? I have a scangauge attached to my car, so I assume I can monitor fuel trims and all that.. but I am still learning to use it and have no idea what any of the gauges actually mean other than the obvious ones like MPG, AVG, RPM, etc.
 
#30 ·
I watched your updated video...your engine makes a hissing sound typical of a vacuum leak. I couldn't hear it when the car was in Neutral or Park but only at full throttle. The air intake is a good place to start your troubleshooting...look for disconnected hoses at the plenum,air box etc.
 
#31 ·
So to clarify; where exactly could a vacuum leak be on my car? At what point in the intake system does the vacuum start? I assume somewhere after the air filter... ? So for example, if one of the screws holding down the air filter housing was missing, I assume that wouldn't cause a vacuum leak right? I am still not clear on exactly where I start the testing, and what all parts I check further down the line (so to speak). Also; still waiting for someone to confirm that using a green Coleman propane canister (the kind used for camp stoves) with a blow torch adapter on it will be appropriate for doing the propane test.

Thanks!
-shawn
 
#37 · (Edited)
Vacuum Leak?

Start watching this video at the 10 minute mark. Its about testing for a vacuum leak on a Chevy Prism(same as Corolla).
I actually watched the whole video (and part 2!). Their Prism/Corolla was a bit different than mine, such as having a MAF Sensor and a slightly different wire setup.. but it was still educational.

At this point I am not able to find any vacuum leak. I tried spraying propane all over the place and no change in RPMs or engine sound/vibration. I even made my own smoke machine from a ball jar and a few plastic tubes and tried blowing smoke into the upper air filter housing (with throttle body open), and then through the brake vacuum hose (from the brake end), and no smoke came out anywhere that I could see except from the air intake.

Combine this with the fact that the mechanic that inspected it said there wasn't a vacuum leak, and it sure seems like there isn't one. Of course I suppose its possible that the mechanic was wrong, and that I'm not doing the tests right (which is totally possible).
 
#39 · (Edited)
That is what the mechanic said. It is entirely possible. There has been some vibration the whole time I've owned the car (about 5 years), but it seems like it has become substantially worse over the past few months. I don't expect the car to last a whole lot longer, but over the past couple weeks I have done about $2500 worth of maintenance stuff, so I am really hoping to get another 1-2 years out of it. My main concern is that the vibration is a symptom of an issue that could eventually translate to an expensive repair. If not, and its really just showing its age, then I'm sure I can cope with it for the remainder of the cars life...

On a side note; it also seems like the gas mileage may of took a turn for the worse in that same time period, but I am not certain because I haven't been tracking it very closely. I do the same drive every morning and it usually averages about 30mpg according to my scangauge, but for the last week its been about 20mpg. I won't know for sure until I fill up my tank again. I have never gotten less than 28mpg, even when doing just city driving.. so if its less than that I will know something is up. I've actually been surprised how good the MPG has been on this car. On long road trips I have often averaged between 38-45+ mpg!
 
#40 ·
I'm still leaning towards a fuel delivery issue, but I might be stretching here since no codes have been set.

I'm thinking a good fuel system cleaning would help a lot and possibly use seafoam to clean the intake track to break up some of the possible carbon deposits on the valves and top of the piston.
 
#43 ·
Ya, it is a tricky issue since the cause is far from obvious, and there are no codes or CEL. Plus, as I said in an earlier post; a well regarded mechanic spent many hours diagnosing the issue and came up with nothing. However, I don't fully trust them and it wouldn't surprise me if they missed something.

For what its worth, I did add some fuel system cleaner to my current tank of gas (I used Chevron Techron "Complete Fuel System Cleaner"), but it seems like such products get mixed reviews about whether they do anything. I suppose the next step would be to go more aggressive with the seafoam, but I hear it can be overly agressive and mess up seals and such? I would hate to make things worse with a product that may not even help the issue.
 
#46 ·
I have not, and I'm not sure if the mechanic checked them or not. I'm pretty sure they have never been replaced in this car since its not mentioned in any of the paperwork (I have all the MTC records since the car was new).

I did a quick search online and it appears that I would need a voltmeter to check them? I don't have one, but I do have an electrician friend that could potentially help. The test looks a bit complicated, and I'm not even sure where the sensors are and which wire to use in the test. Can you provide any additional info about how to do this?

Thanks,
-shawn
 
#50 ·
Penetrating oil + time + heat from torch + muscle = all bolts come free.
May sound counter productive but try tightening the bolt if it wont budge all you need is a tiny bit of movement to take the rust off and you will get it.

Also wanted to mention since price of two new o2 sensors is a factor DO NOT BUY CHEAP ONES you will cause more issues than you started with. You need to buy denso or NGK.

http://www.rockauto.com/en/moreinfo.php?pk=991892&cc=1432913&jnid=371&jpid=0

http://www.rockauto.com/en/moreinfo.php?pk=991963&cc=1432913&jnid=371&jpid=2


Dont forget to add a discount code from a search online before you order with rockauto but this way you save money. Also once you select your o2 sensors to the cart a little van will appear next to other items you may wish to order the van means ships from same location so you can save even more. I love rock auto for that feature.
 
#52 · (Edited)
Penetrating oil + time + heat from torch + muscle = all bolts come free.
May sound counter productive but try tightening the bolt if it wont budge all you need is a tiny bit of movement to take the rust off and you will get it.
Thanks for the tip. I was planning on doing some research on how to remove rusty bolts, and that gives me a good head start.

Also wanted to mention since price of two new o2 sensors is a factor DO NOT BUY CHEAP ONES you will cause more issues than you started with. You need to buy denso or NGK.

Dont forget to add a discount code from a search online before you order with rockauto but this way you save money. Also once you select your o2 sensors to the cart a little van will appear next to other items you may wish to order the van means ships from same location so you can save even more. I love rock auto for that feature.
I was planning on getting Denso if I buy new ones since the Toyota Dealer said their OEM parts are Denso Brand. Wow, Rockauto is really cheap! The same parts are nearly twice as much at the main auto parts stores (Autozone, O'Reilly, etc), and the same part at the dealership is 4x as much!

If I can get both sensors for under $100 then I might just go ahead and replace them whether they are bad or not. I assume its probably a good idea either way since I think they are the original sensors and it seems people say they should be replaced after 100k? Given that mine most likely have 250k on them, I am guessing they are due for replacement.

Thanks,
Shawn

**EDIT: I went ahead and ordered the Denso O2 sensors that you provided links for. They should be here early next week, and I will report back once I have them installed.
 
#55 ·
I have been seeing info that sometimes an o2 sensor can start to fail but not throw any codes. Perhaps that is the situation with my car? Either way, I am going to replace them and see what happens. As I said above, the sensors appear to have never been replaced, and from what I hear they usually last between 60k-100k+ depending on maintenance, so I figure it probably wouldn't hurt to replace them given that they probably have 250k on them! Who knows if my car will run better, but I figure its worth a shot. :)
 
#56 ·
First i generally do not approve of tossing parts without diagnostics. You say you have complete records of the cars history and did not see a o2 sensor job yet so to replace them due to age and milage is fine. You will likely see a small mpg improvement with the new sensors.

I hope you found a discount code to save on shipping. Ive reffered so many people to rock auto i should have stock options with them. :)
 
#57 ·
Yes, I have all records for everything done to the car since it was brand new. As far as I can tell, the o2 sensors have never been replaced. A small MPG improvement sounds good, and if anything else good happens then all the better! :)

I did find a 5% discount code, which paid for the shipping. Thanks!
 
#65 ·
The connector is about 2" away from the hole in the floor. Undo the sill guard holding the carpet edge onto the door opening. Remove side plastic panel under glove box. Free up carpet in that corner and start peeling towards the back. At some point, you'll find the hole in floor where O2-sensor cable goes through along with connector.

Don't have to do anything with cable going to ECU.
 
#68 ·
The connector is about 2" away from the hole in the floor. Undo the sill guard holding the carpet edge onto the door opening. Remove side plastic panel under glove box. Free up carpet in that corner and start peeling towards the back. At some point, you'll find the hole in floor where O2-sensor cable goes through along with connector.
Thank you for the info! I will check it out this afternoon and hopefully won't have any more questions.
 
#69 ·
Update: It took me 3 days, but I finally have the new o2 sensors installed. I managed to find a similar stud at an auto parts store, and ended up using plain steel nuts since I couldn't find ones that matched the originals. I ended up also adding split lock washers and threw on some thread lock for the heck of it. Not sure if all of that was a good idea, but I didn't want the new nuts to come loose.

When I started the car, there wasn't a CEL light, so I assume that means the new sensors are good and installed correctly. However, there was a ton of smoke that was coming from under the hood! I am guessing its from PB Blaster that I sprayed around to get the nuts loose.. and perhaps from the thread lock stuff as well? I am hoping its not exhaust that is somehow leaking out. Anyways, I shut everything down and decided to give it a day before proceeding so that the thread lock can cure, and because I needed a break from dealing with my car! I will report back tomorrow about the smoke and whether or not the new sensors made any difference with the vibration issue.
 
#70 ·
Good job!

Even if its not good work you stuck with it and tried. If there is an issue tomorrow you can dig in again and again until you get it right. Gets addictive working on your car you will see. ;)

When you start the car tomorrow get out and try to pinpoint where the smoke is coming from. If its out of the front o2 gasket thats bad and you will set a code but if its just burning all the oil you sprayed then give it a good long drive and see how it feels.

One last note. I assume you disconected your battery while working on your electrical sensors (safety first) that is why the engine light is off. You will need to complete all of the drive cycles to set the monitors before you know if the light is off for good. Do not panic if it returns unless the light is flashing. Flashing engine light is very bad do not drive if this ever happens just pull over and scan immediately.
Again congrats on the hard work you did.
 
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#71 ·
One last note. I assume you disconected your battery while working on your electrical sensors (safety first) that is why the engine light is off. You will need to complete all of the drive cycles to set the monitors before you know if the light is off for good. Do not panic if it returns unless the light is flashing. Flashing engine light is very bad do not drive if this ever happens just pull over and scan immediately.
Again congrats on the hard work you did.
Thanks! Actually, I did not disconnect the battery. I looked at numerous online videos/websites about how to replace o2 sensors and it was never mentioned. It also wasn't mentioned in the instructions that came with the new o2 sensors. Just to be clear; the CEL light was never on. In fact, it has never come on while I have owned the car.

I plan to take a drive later this morning, and will report back afterwards.
 
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