Could be a bad motor mount or trans mount. You could try to jack the motor starting at the trans mount. When the vibrating occurs, the increased angle should take away most of the vibration. Alternatively, it could also be the tensioner pulley. Try hand cranking the tensioner pulley. You can also remove the belt and run the engine. Don't run the engine too long without the belt. Can cause damage to your motor.

 

I jacked up the passenger side motor mount mount and noticed no difference. I will try to get to the other mounting points and see what happens... Come to think of it my belt tensioner makes a rough noise intermittently and once the car warms up I get a tiny bit of belt squeal when in gear... So I can just remove the belt and run it just long enough to put into gear and test it?

 

If you run too long without the belt, it will severely damage the motor. Just till it goes into gear. Or hand crank with belt on.

 

Has the throttle body been cleaned?

 

Yes when I replaced the throttle body gasket I took it all the way off and cleaned it

 

I don't know if that side of the motor is hot. It only happens at operating temp?

 

Yes only at operating temperature

 

Having the AC on helps tame about 80% of the vibration as well.

 

OK I replaced the belt and belt tensioner.
The engine runs much smoother now that the tensioner shock isn't popping.

There is still a vibration though.
I've checked and tested motor mounts and it feels more like the engine itself is doing something... Fuel trims look excellent and it is getting great MPG.

Gets much much better with AC on.

 

What rpm is it idling at? How is your crankshaft pulley's elastomer damper? Your motor/tranny mounts and engine isolator (upper right mount) may be hardened and deteriorated.

 

Right at 750 in Park, and 650 in gear.
I haven't checked the crankshaft pulley.

 

This is the front engine mount... It looks like the bolt has been wearing on the housing... They all seem to have some give, but this one was more noticeable.

 

Can you not tighten the bolt?

 

Nope it's super tight... Do all the brackets have a bolt hole that is made like that or is it only from wallering around?

 

UPDATE!!!

Changed the front motor mount and it was indeed warn.
The change made no difference and maybe even made it a more rigid vibration.

When I jack up the engine around the passenger side motor mount it gets way worse.
The engine is running great and fuel trims stay right around 0% at all times.

When the AC is on it obviously idles up slightly and causes the vibration to diminish, but the once it gear if you turn the AC on/off the car will lurch. It may be normal since it is such a strain on the engine to run the AC.

Any ideas?

 

I have the same vibration in drive. When coming to a stop the idle sometimes dips and slightly shudders but recovers. Oddly, I've noticed it only does it after (for instance) driving it for the first time in the day... then i stop at a convenience store, get back in and restart the car, put it in drive, and thats when it happens. Won't shudder or vibrate on the first drive of the day; Only after restart it happens. Even then it kind of sorts itself out and does it only 25% of the time (which is still too much and drives me nuts).

I've changed intake manifold gasket to the new orange one (helped a bit), cleaned MAF, changed PCV and the hose, cleaned throttle body, cleaned IACV, changed spark plugs, air filter, and replaced the fuel injector o-rings and grommets. I'm starting to think its a fuel filter issue (which is supposed to be a lifelong part), maybe the actual intake manifold (which is plastic) has an invisible crack (vacuum leak), or the injectors need to be replaced.

Seems like everyone has this issue but nobody has found the exact reason :/

Edit- no trouble codes have ever been thrown

 

I have the same vibration in drive. When coming to a stop the idle sometimes dips and slightly shudders but recovers. Oddly, I've noticed it only does it after (for instance) driving it for the first time in the day... then i stop at a convenience store, get back in and restart the car, put it in drive, and thats when it happens. Won't shudder or vibrate on the first drive of the day; Only after restart it happens. Even then it kind of sorts itself out and does it only 25% of the time (which is still too much and drives me nuts).

I've changed intake manifold gasket to the new orange one (helped a bit), cleaned MAF, changed PCV and the hose, cleaned throttle body, cleaned IACV, changed spark plugs, changed battery and air filter, and replaced the fuel injector o-rings and grommets. I'm starting to think its a fuel filter issue (which is supposed to be a lifelong part), maybe the actual intake manifold (which is plastic) has an invisible crack (vacuum leak), or the injectors need to be replaced.

Seems like everyone has this issue but nobody has found the exact reason :/

Edit- no trouble codes have ever been thrown

I'm fixing to change the transmission mount this weekend.
At this point I am highly suspect of the VVT solenoid not closing all the way after it gets warm. It has all the correct symptoms of it including showing 9.0 ohms at 68 degrees when spec is 6.9 - 7.9 ohms.

I can see daylight through it and think maybe the internals are wearing out.

 

My wife drove the Matrix yesterday and said for once she actually noticed the vibration.
I got in to drive it and the vibration in park was MUCH worse than when it was Drive or Reverse before the front mount swap.

I loosened the front engine mount up and it acted like it was in a serious bind but didn't help the vibration.
The new mount is extremely stiff in comparison to the old mount, but I think the old one was soft enough to help absorb a lot of vibration.

Going to put the old one back on, and if the vibration is dampened then i'll just leave it on there and move on.

Just wanted to give a quick update on that.

 

Changed the mount and noticed that when they replaced the transmission last year they put the engine mount bracket on too low in the front causing the mount to bottom out.

The other mounts look good but I'm going to spend some time checking all the brackets to see if the 3 that are attached to the transmission are incorrectly placed.

 

UPDATE!!!!!

I'm so happy to let you guys know that the vibrations are completely gone!!!

Here is what happened.
I replaced the front engine mount but the vibration got substantially worse. I then unbolted it and noticed that the vibrations were better than with the original mount. I compared the old mount with the new mount and noticed the new one was extremely stiff.
I then noticed the reason why the vibration had gotten better when I unbolted the mount was because the mount bracket that is bolted to the transmission was WAY to low.

So I raised it up so it was aligned with the mount, then when I bolted it back on it didn't create more vibration.

I then replaced my transmission mount and noticed that it was hard and brittle. I swapped it out with a softer mount and it GREATLY reduced the vibration. I put jack pressure on my passenger side mount and Viola!!! It was completely gone!!

I have ordered that mount and will be replacing it as soon as it comes in.
I had ordered one aftermarket brand mount for the front that was way too stiff. So after returning it and ordering another I am very happy with the MotorKing mounts. When I compared the stiffness and quality vs a new OEM mount, it is the closest I found.

So right when you're ready to rule out engine/transmission mounts, take them off easiest to hardest and document the differences.:thumbsup:

 

I was dreading that it might be the motor/transmission mounts. After you get them replaced, report back with an update after a few weeks pass.

 

Update on my vibration issue: Automatic 2003 Corolla-

My problem seems to have been different from HighlanderMatirx. My issue was failing Oxygen sensors (upstream was the issue but I replaced downstream as well) not being able to correct the air/fuel mixture fast enough to return to a smooth idle while in drive when coming to a stop. There was a sudden split second vibration/dip in the idle but would usually return to normal.

My oxygen sensors were "lazy" so if you have this problem and there is no other indication something is wrong (ex- check engine light, or codes thrown) the only way to know is to remove and check the oxygen sensors visually, or use a scan tool to check with a graphing feature. Only noticeable issue I had was the dip in idle.

 

My oxygen sensors were "lazy" so if you have this problem and there is no other indication something is wrong (ex- check engine light, or codes thrown) the only way to know is to remove and check the oxygen sensors visually. Only noticeable issue I had was the dip in idle.

You should be able to view this by watching the front o2 sensor reading on a scantool as well.

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