98 v6 firebird A4 vibrates at a stop, in park or Neutral
 

1998 3.8 v6 Firebird 4L60E L26 swap. Vibration started a few months after the swap. 204k on the body, 30k on the new engine after the swap. the L26 had under 100miles when it was installed.

My car is vibrating like crazy. Here is everything i have fixed or tried.

New rubber Motormounts
New Harmonic balancer (98-02 balancer)
New rubber Transmission mount
New Plugs and wires
New Fuel filter
Rotated the flexplate to see if that changed the vibration didnt help.
Also inspected the flexplate for stretched bolt holes. They are fine.
Took the serpentine belt off and it didnt change the vibration.
Checked the exhaust and its not touching the body.
Had a shop check the catalytic converter, its not plugged and im getting 26mpg on the highway.

Car has new motor mounts, motor doesnt move under acceleration. Mounts have been double checked to be tight and bolted down correctly.

Car vibrates no matter what gear its in while stopped.

Car does NOT vibrate while going down the road.

Only vibrates at a stop with the foot on the brake or at a stop in park. If i rev the engine in park/Drive at a stop over 1000k the vibration goes away.

Im at wits end with this thing. I drive it 100miles daily to work so it isnt hurting the reliability, its just annoying and embarassing to be vibrating at every light and stop sign.

I jacked it up lastnight and started it and when i put my hand on the transmission pan you can feel the vibration, but its stronger on the engine oil pan. I even took the dust cover off the flexplate and watched it spin and its not wobbling.

Im not getting codes or and SES light. This has me stumped.



Next thing to check are my fuel injectors. Any other ideas guys??

Re: 98 v6 firebird A4 vibrates at a stop, in park or Neutral
 

Rotate your converter by hand and see if any weights have came off. It's easier to tell if it's an aftermarket (painted) converter.

Frank

Re: 98 v6 firebird A4 vibrates at a stop, in park or Neutral
 

Thanks Frank, I'll check it out tonight. I was really hoping it wasnt the transmission or converter. But its coming down to I dont know what else to check. Really wish it was throwing a code.