I've never heard of , or experienced the low idle problem, I have an 06. If your idle is low , it's probably not a vacuum leak as this would make the idle/revs go higher than normal.
Did you have the same problem before you changed your spark plugs? Did you buy OEM Denso or NGK iridium plugs?

Did you replace the air filter? A hot engine needs more air than when cold.

It's strange that no codes are showing and two mechanics said different things. I agree with you if the mounts were bad , it would act the same all the time but if you're seeing your rpm lower than normal , it's not the mounts.... Good luck

 

Just recently purchased the car. Only had it for a week or so before it went to my friend to replace the front bumper, paint back bumper, front brakes, etc. etc. The air filter is new, the plugs are OEM Denso plugs. It is really hard to tell if this issue was there prior to all this as I only really drove the car off traffic times and never idle in traffic more than a few times, but I do not recall.

What the 1st mechanic stated is that his reader is showing about 150 rpm's lower then the gauge. He also stated to bring up the car to about 1,000 rpm's in neutral at a stop light, and see how the idle smooths out. If I put on the defroster, the idle sometimes kicks up and smooths out, so it is very possible that is it idling too low. The 2nd mechanic did not check the idle, but quickly scanned the car, again with no errors.

As mentioned before, the idle roughness is only when fully warmed up. I am only looking for guidance on what to have a mechanic check first. I will not go the route of engine and transmission mounts unless there is a written guarantee, which I doubt any mechanic will give you. My mother has a 2006 Honda Civic (140K on the clock) and as smooth as can be. My friend has a 2012 (140K on the clock) and very smooth.

It appears that there have been too many members who have posted results after mounts replaced only to have the same idle issues (usually warm engine). Thanks!

 

Just recently purchased the car. Only had it for a week or so before it went to my friend to replace the front bumper, paint back bumper, front brakes, etc. etc. The air filter is new, the plugs are OEM Denso plugs. It is really hard to tell if this issue was there prior to all this as I only really drove the car off traffic times and never idle in traffic more than a few times, but I do not recall.

What the 1st mechanic stated is that his reader is showing about 150 rpm's lower then the gauge. He also stated to bring up the car to about 1,000 rpm's in neutral at a stop light, and see how the idle smooths out. If I put on the defroster, the idle sometimes kicks up and smooths out, so it is very possible that is it idling too low. The 2nd mechanic did not check the idle, but quickly scanned the car, again with no errors.

As mentioned before, the idle roughness is only when fully warmed up. I am only looking for guidance on what to have a mechanic check first. I will not go the route of engine and transmission mounts unless there is a written guarantee, which I doubt any mechanic will give you. My mother has a 2006 Honda Civic (140K on the clock) and as smooth as can be. My friend has a 2012 (140K on the clock) and very smooth.

It appears that there have been too many members who have posted results after mounts replaced only to have the same idle issues (usually warm engine). Thanks!

I have same issue,…..exactly. I replaced IAC. Idle air control valve $90-125
Have you done this?

 

I would try some Chevron Techron fuel injector cleaner anb about 50 miles driving. If there is a significant improvement then keep driving. For an initial treatment go slightly over the recommended concentration, like a bottle for 8-10 gallons in the tank.

 

Thank you Old Mechanic. I have already gone through 2 bottles of Lucas fuel treatment. First bottle in its entirety on 13 gallons. Second bottle was split for the next 2 tanks. This was done prior to the intake manifold gasket.

I am curious to know if an experienced mechanic can determine with the proper diagnostic equipment if the proper idle, air/fuel mixture, and if any cylinders, coils, etc. are misfiring.

Spending nearly $1,000 on the mounts, or idle speed motor, or replacing parts haphazardly just does not make sense.

 

I am curious to know if an experienced mechanic can determine with the proper diagnostic equipment if the proper idle, air/fuel mixture, and if any cylinders, coils, etc. are misfiring.

Yes, and this is the question that you should be asking. Someone with the proper scope meter can view the ignition wave pattern for each of your cylinders. If a cylinder is misfiring this will further point to whether the issue is from within the combustion chamber or external to the chamber, which will aid in further diagnostics.

Looking at the LT and ST fuel trims over time may also be of help. Has anyone yet looked at your fuel trim data? How about the O2 sensor voltage change?

If your condition is not present when first starting (cold) yet appears after it warms up, that could be telling you the issue starts as soon as the engine enters into closed loop.

I would live with it for now until it gets worse or you find someone with the ability to do the above mentioned diagnostics.

 

Verify that the new intake manifold gasket is orange.

 

Chevron Techron Fuel System Cleaner (not the less expensive Fuel Injector Cleaner) has a good amount of PEA in it and might help with the issues you describe better than Lucas Fuel System Conditioner (no PEA I am aware of)...make sure to use Top Tier gasoline (many choices available...go to Top Tier website to see if your choice is one) of the proper octane...don't use higher octane unless your vehicle calls for it...

Good Luck,

Bill

 

Chevron is the only one I recommend, seen it wake up a basically dead cylinder (pre OBD2 car) to clear the CEL on an Echo in 50 miles (lean misfire code).

What have you got to loose versus what to gain. end of problem chance is significant. I would not want to be the tech who tore your fuel rail apart pulled the injectors, found different patterns and flow volumes, then was so honest I told you you could have put Techron in and solved your problem and haded you a bill for hundreds of dollars. That's why I started a customer on Techron before chasing a difficult diagnoses and handed you the bill. That's the backwards way to diagnose anything and brought me customers who would not go anywhere else, even within a 200 mile radius.

 

Verify that the new intake manifold gasket is orange.

Yes, the new intake manifold gasket is orange.

Chevron Techron Fuel System Cleaner (not the less expensive Fuel Injector Cleaner) has a good amount of PEA in it and might help with the issues you describe better than Lucas Fuel System Conditioner (no PEA I am aware of)...make sure to use Top Tier gasoline (many choices available...go to Top Tier website to see if your choice is one) of the proper octane...don't use higher octane unless your vehicle calls for it... Good Luck,

I will try Chevron fuel cleaner. As mentioned previously, the vehicle runs great. Running anything but regular unleaded, outside 87 Octane, or higher Octane even from a Top Tier company has not been suggested on this forum and others, unless I am wrong otherwise. My BRZ (2017) takes super (93 Octane) and I only run Shell V Power and Sunoco/Exxon where Shell stations are not nearby. The engines have been designed for premium gas companies.

Question(s):

What should I ask the mechanic to go over? What other items, etc.? I will not go the route of engine and transmission mounts or idle speed motor (approximately $1,000 each) only to find out this was not the issue. A good mechanic should be able to exhaust all other avenues before assuming it is the above mentioned 2 items.

 

??? recently purchased car and have now dumped $$$ into it. From a dealer or individual ? Dealer should have had some sort of warranty and individual is this why it was sold?

Was a problem determined to be with the old intake gasket as to why it was changed?

How did plugs look? All the same ?

Your idle speed motor is that an IAC ? Accessible to clean? EGR system good? IAC can be found for $50 or so.

What engine is in your car?

To get an idea about bad mounts we used to shift from P-D-R-D etc with foot on brake and watch engine to see if jumping excessive.

 

If you have an idle issue and the intake was PROPERLY changed to the orange intake manifold gasket and also did plugs, and also verified there are no vacuum leaks it is most likely the injectors.

 

If you have an idle issue and the intake was PROPERLY changed to the orange intake manifold gasket and also did plugs, and also verified there are no vacuum leaks it is most likely the injectors.

There needs to be verification on the vacuum leaks first and foremost to determine. I will be calling the mechanic today. Yes, to the orange intake and yes to the plugs.

??? recently purchased car and have now dumped $$$ into it. From a dealer or individual ? Dealer should have had some sort of warranty and individual is this why it was sold?

Vehicle purchased off a friend for almost exactly what dealer was offering on a trade. This excess vibration was not as bad there originally and this is why I took it to the 1st mechanic.

Was a problem determined to be with the old intake gasket as to why it was changed?

The 1st mechanic stated that he will have to change the intake first so see if the idle problems gets better. He would not look at anything else besides this and it was never changed, so a good time to change it. After this, the idle actually was not too bad. It has become worse over the last week or so.

How did plugs look? All the same ?

Your idle speed motor is that an IAC ? Accessible to clean? EGR system good? IAC can be found for $50 or so.

This car is the first year with the DBW throttle body (all one piece) and is not separate? The prices are high and have all the part # 's. EGR, not sure and I will have the mechanic look at it. The 2nd mechanic seems more open minded.

What engine is in your car?

1 ZZ

To get an idea about bad mounts we used to shift from P-D-R-D etc with foot on brake and watch engine to see if jumping excessive.

The 2nd mechanic did this, and stated mounts were bad. $550 for OEM like quality, but that scares me. OEM is higher. I want to rule everything else out first.

 

Chevron is the only one I recommend, seen it wake up a basically dead cylinder (pre OBD2 car) to clear the CEL on an Echo in 50 miles (lean misfire code).

What have you got to loose versus what to gain. end of problem chance is significant. I would not want to be the tech who tore your fuel rail apart pulled the injectors, found different patterns and flow volumes, then was so honest I told you you could have put Techron in and solved your problem and haded you a bill for hundreds of dollars. That's why I started a customer on Techron before chasing a difficult diagnoses and handed you the bill. That's the backwards way to diagnose anything and brought me customers who would not go anywhere else, even within a 200 mile radius.

Will go out and purchase Techron today.

Yes, and this is the question that you should be asking. Someone with the proper scope meter can view the ignition wave pattern for each of your cylinders. If a cylinder is misfiring this will further point to whether the issue is from within the combustion chamber or external to the chamber, which will aid in further diagnostics.

This is exactly what am looking for.

Looking at the LT and ST fuel trims over time may also be of help. Has anyone yet looked at your fuel trim data? How about the O2 sensor voltage change?

No, not yet. I will ask them to look at the LT and ST fuel trims over time, and the O2 sensor voltage.

If your condition is not present when first starting (cold) yet appears after it warms up, that could be telling you the issue starts as soon as the engine enters into closed loop.

What factors contribute to the rough idle in a closed loop? Unfortunately mechanics sometimes are not open minded to these options.

I would live with it for now until it gets worse or you find someone with the ability to do the above mentioned diagnostics

Exactly what I am doing for the next week. I will add a bottle of the Techron and see how it goes.

 

Can anyone recommend a "quality mechanic" in the Middlesex, Monmouth, Ocean, and Mercer Counties of NJ? Someone that understands these types of vehicles.

 

What size engine?

Look like this?

 

Dane:

The engine is a 1ZZ-FE engine. It is a 2005 Corolla with a 1.8 16V (USA built) as I spoke to Toyota directly.

 

Should be able to do a drag and drop file upload ??

 

This is the original plug from the car at 80,000 miles. All plugs looked similar.

 

plug looks good to me...

Chevron Techron Fuel System Cleaner is currently on sale if you have one near you... https://shop.advanceautoparts.com/o/aap-flyer

Bill

 

Costco has $8 off (6 pack) on the injector cleaner right now. Picked up a 6 pack even though I have a bottle left. Just over $14 for 6 bottles. Had a 92 Sentra that lost a cylinder completely at anything under 2k RPM and stalled every time you stopped. Cleaned the IAC and drove it 19 miles with the Techron and it ran perfectly. Bought for $300 sold for $1200, nice little pluck after driving it 10 k miles, basically for free. Averaged 36 MPG with 190k on the odometer. That 1.6 liter Nissan engine was as good as anything ever made, no t-belt, no valve lash, plugs at 100k. I think the cap and wires were original, maybe even the rotor.

 

Costco has $8 off (6 pack) on the injector cleaner right now...

Chevron should start paying you some commissions

 

Thanks Silver Sport. I doubt the fuel cleaner will make a difference, but will give it a shot. Yesterday, I went to go see another reputable mechanic where you can actually see them working on your car. He is very reasonable for diagnosis. The whole situation was explained to him and he is ruling out engine and transmission mounts, but I now feel a vibration in my right leg while driving.

He will scan and scope the vehicle as per the recommendation to check out the car in detail. We have to rule out vacuum leaks, coils, and other items before going onto the expensive stuff. He did however say that the car was idling too low (his best guess), which puts me back at the idle speed motor (all one piece) and throttle body. The OEM is like $800, but after market new is like $400 and re-manufactured is like $150-$200.

Once completed on Thursday, I will post up what his findings are. Based on my findings the idle speed of the car should be 650-750 rpm, which looks to be accurate on the dash gauges, but the 1st mechanic said car was idling 150 rpm's lower than gauge on his scan tool. The issue is in Park, the RPM's rise, but do not smooth out, and this does concern me as the car is idling higher with no load on transmission or torque converter (I believe this is what happens). Only time will tell. Thanks!

EDIT:

Thanks Old Mechanic. I will go to Costco today and pick up the fuel cleaners. Although, I still want a full diagnosis as waiting another 2 tank fulls will be weeks, etc. I believe the most is about 1 hour- 2 hours labor, in where he will back off from any work done. Piece of mind is better than a few $$ at this time. As mentioned previously, on the mounts I am against if every other option is exhausted.

 

He will scan and scope the vehicle as per the recommendation to check out the car in detail. We have to rule out vacuum leaks, coils, and other items before going onto the expensive stuff. He did however say that the car was idling too low (his best guess), which puts me back at the idle speed motor (all one piece) and throttle body. The OEM is like $800, but after market new is like $400 and re-manufactured is like $150-$200.

And used throttle body $50 !!

 

Aisin new OEM part is $230 on rockauto

 

This is where I looked on Rock Auto.

https://www.rockauto.com/en/catalog...om/en/catalog/toyota,2005,corolla,1.8l+l4,1433059,fuel+&+air,throttle+body,6472

Tech Smart is brand new at $454.79. Aisin TBT007 is $236.79, and this is the lesser of, but does not state if new or re-manufactured. Cardone is new at $203.79. There is an economy section, but hard to figure out. I would take the Aisin any day for $236.79.

This all assumes that this is the issue. Hopefully on Thursday, we can get to bottom of this and rule out vacuum leaks, coil packs, fuel injectors, oxygen sensors, or any other miscellaneous item that it could be. Will keep everyone posted.

 

Those Aisin on rockauto are new

 

the stuff at Costco is a fuel injector cleaner and not a fuel system cleaner (more PEAs) so you can buy the stuff from Costco but it is not going to do what has been suggested...

Good luck with your choice

Bill

 

the stuff at Costco is a fuel injector cleaner and not a fuel system cleaner (more PEAs) so you can buy the stuff from Costco but it is not going to do what has been suggested... Good luck with your choice
Bill

Purchased a 6 pack yesterday at Costco and used 1 bottle and filled up with Costco Regular Gas. They are a top tier company. If this is not a good thing, then what exactly is the best on the market with the most PEA's to get the car back in shape?

Quote: Originally Posted by DaneH View Post And used throttle body $50 !! I paid $40 for a spare OEM used that I took off LOL!

Here is the strange part. Car was not idling well before the manifold gasket change. Reset the computer after cleaning throttle body and MAF. Really no change, but a little worse, again before gasket change on January 2nd. After gasket, no reset of computer.

Drove car for about 10 days, and it seemed like the car's idle did not improve. Then cleaned MAF one more time (I missed one hidden section), and inspect throttle body and it was very clean (left alone). Reset the computer, by disconnecting the negative terminal on batter, and car actually failed to start on the first time a few times, but never happened again. A few days later, I took the car to mechanic and he stated engine mounts were bad, then took to another mechanic and he the idle is too low. This is about 7-9 days of a time span.

Now, yesterday, on the 10th day, all of a sudden drove the car throughout the day. It was started at least 5X and the engine was able to cool off for a while because of extreme cold weather and it appears that the roughness has changed to the point where now the idle is pretty smooth in park, a lot better in drive and worse in reverse, but not shaking that much. Hopefully the computer is now recognizing the idle during the reset. It is not 100%, like my 16 Avalon, but I am happier. The first time, the car was a little rougher than the last time, so hopefully, the ECU is still trying to get the idle to where it needs be.

I will still bring the car on Thursday to the mechanic to thoroughly review everything and rule out all possibilities. If the car comes clean "In a good state of tune", the only other items that it could be is the motor and transmission mounts which will be a difficult decision. Although, I can live with how the car is running now (at least yesterday). Today is a different story. I will take the car out in about one hour for a 30 minute drive just to have it moving to see if the idles is still somewhat smooth or not.

I am also hoping that the cheap tires that the previous owner placed on the car along with front and back (shocks and struts) is also a minor reason for the ride and rough idle, but who knows. After the drive, around 10 a.m., I will report back with how the car runs.

 

Purchased a 6 pack yesterday at Costco and used 1 bottle and filled up with Costco Regular Gas. They are a top tier company. If this is not a good thing, then what exactly is the best on the market with the most PEA's to get the car back in shape?



Here is the strange part. Car was not idling well before the manifold gasket change. Reset the computer after cleaning throttle body and MAF. Really no change, but a little worse, again before gasket change on January 2nd. After gasket, no reset of computer.

Drove car for about 10 days, and it seemed like the car's idle did not improve. Then cleaned MAF one more time (I missed one hidden section), and inspect throttle body and it was very clean (left alone). Reset the computer, by disconnecting the negative terminal on batter, and car actually failed to start on the first time a few times, but never happened again. A few days later, I took the car to mechanic and he stated engine mounts were bad, then took to another mechanic and he the idle is too low. This is about 7-9 days of a time span.

Now, yesterday, on the 10th day, all of a sudden drove the car throughout the day. It was started at least 5X and the engine was able to cool off for a while because of extreme cold weather and it appears that the roughness has changed to the point where now the idle is pretty smooth in park, a lot better in drive and worse in reverse, but not shaking that much. Hopefully the computer is now recognizing the idle during the reset. It is not 100%, like my 16 Avalon, but I am happier. The first time, the car was a little rougher than the last time, so hopefully, the ECU is still trying to get the idle to where it needs be.

I will still bring the car on Thursday to the mechanic to thoroughly review everything and rule out all possibilities. If the car comes clean "In a good state of tune", the only other items that it could be is the motor and transmission mounts which will be a difficult decision. Although, I can live with how the car is running now (at least yesterday). Today is a different story. I will take the car out in about one hour for a 30 minute drive just to have it moving to see if the idles is still somewhat smooth or not.

I am also hoping that the cheap tires that the previous owner placed on the car along with front and back (shocks and struts) is also a minor reason for the ride and rough idle, but who knows. After the drive, around 10 a.m., I will report back with how the car runs.

the Costco fuel is fine...it is what I use as well...I was referring to the Costco bought Chevron Techron Fuel Injector Cleaner you bought instead of the Chevron Techron Fuel SYSTEM cleaner that was recommended here in your thread...the fuel system cleaner has far more PEAs to do the clean up...good luck with your Corolla...

Bill

 

I can see further posting by me on this thread will only cause the thread to be hijacked by someone who wants to call me a liar. Hope you can get the issue resolved.

 

My apologies - was teasing but did not mean to offend you. I see you post in a lot of threads about fuel system cleaner and they can work. The ECU has about + 35% in fuel trim leeway before a lean code is triggered.

A problematic injector or two can therefore fly under the radar - not setting off any check engine lights - and cause performance problems. A high quality cleaner with can work in these instances.

 

I can see further posting by me on this thread will only cause the thread to be hijacked by someone who wants to call me a liar. Hope you can get the issue resolved.

I am with you Old Mechanic. I do believe that they do work. Bottle is in the tank and will keep you posted.