Matrix Diesel Wobbling at 40 mph
 

Hi all. My 02-03 Matrix Diesel has developed a wobbling sensation at arond 35-40. Comes through the gas pedal and is at its worst in 4th gear.

Have had tyres balenced and no difference.

Any ideas, I'm thinking engine mount or hub.

Does anyone else have or had the same problems. PLease get in touch its driving me nuts!!!

Your description is to vague. Is it the motor or the wheels vibration. You can find out by driving the car down the road, and coast in neutral. Does it change when you do that?

Doesnt do it in neutral. I can feel it through the steering, but the sensation comes more through the gas pedal. It feels as though something is bent or warped.

It is hard to describe until you feel it. Really feels like a slightly buckled wheel, but I've ruled that out.

Chances are really high you have a bad tire. How many miles are on the tires? Did you rotate them on time? What brand/make are they? Don't skimp on tires.

Tyres are good, bridgstone and avon. But I've swapped the front wheels to back and still the same problem, but thats exactly the sprt of thing it feels like.

When was the last time that car was aligned?

Not sure. This was my first port of call, but the garage recon that Tracking wouldnt cause it.

You think it might?!

No, I don't think alignment has anything to do with it. A consistent wheel wobble like that is caused by:

Distorted Tires (not obvious when balancing is done)
Bent Wheels (Obvious when balancing is done)
Axles (Possible, but not likely)
Bearings (would make a lot of noise)

If you step on the brakes and it vibrates, it could be:

Brakes
Tie Rods
Ball joints

So you see, it's almost always a tire issue. Have a mechanic drive the car and verify the problem.

After reviewing your case again...

You said it DOESN'T vibrate while in neutral while coasting down the road??? Is that true???

If so, then it's not the tires or wheels vibration. It's a motor mount.

Yes, it could be the alignment. Under the power the wheels are pulling the car. When coasting the wheels are being pushed by the car. If there is enough slack in the system the front wheels could become misaligned under power while fine at rest.

http://www.aa1car.com/library/tr295.htm