Mystery Vibration

I have a 2004 Pontiac Vibe, and I’ve been having a problem with vibrations in the car frame. Two separate mechanics diagnosed the problem as worn engine mounts, so I replaced all three, but the problem persisted. I brought it back to the shop, and they (re)replaced one of the engine mounts, saying the problem was that the rubber inside was too dense to properly absorb vibrations, and tweaked the alignment for all three mounts. They gave me the all clear, and yet the vibration started up again on my ride home. ARG.

The vibration is coming in through the seat, the steering wheel, and the floorboards, both passenger and driver side. I haven’t personally tested the back seat, but I would assume it’s vibrating back there as well. This occurs mainly when I am at a full stop at a red light. No vibrations when I first turn on the engine, and none while it is in motion. The longer I sit at a light, the worse the vibrations get. They also seem to get more intense the longer I am driving. Any ideas?

Any check engine lights? I am thinking engine miss may be the source of your problem.


Your car is essentially a Toyota Matrix, I believe

As such, your car needs either genuine Toyota brand parts

What brand mounts did the mechanics install?

The reason I’m asking is that I’ve had very bad luck with some aftermarket mounts.

No check engine lights… the mechanics asked me about that as well.

The parts are definitely Toyota - they went to Pontiac first and were quoted something absurd before being forwarded to the Toyota manufacturer. I trust these guys as far as regular parts and service go, but they don’t seem willing to take on a problem car.

When my MAF was dirty, it idled poorly, but ran fine. No codes were present. You can try cleaning the MAF with sensor safe cleaner. Also, you IAC could be dirty and need cleaning. That is where I would start.