I have been trying to find the source of a vibration i have and got a suggestion yesterday to back off the torque converter. I did today, the vibration was still there when i reved the motor but not as severe. I felt the vibration after about 2250 rpm - 3500 rpms. I decided to bolt everything back up and when i tried to bolt the tc back to the flywheel i noticed that the bolt holes for the torque converter are about a 1/4" away from the holes in the flywheel for it. When i tighten the bolts it pulls the flywheel in towards the tc. The TC seems bottomed out in the flywheel though. I tried my best to take a good picture of it but the best i could get was this.

So i pulled the ecm fuse and had someone crank the car over so i can see the flywheel move slowly. It's definately warped. I figured i'll just replace the flywheel on my next day off, but that dosn't explain why it still vibrates when i'm at speed, put it in neutral and shut the motor off.

Anyone hear of something similar to this happening before?

Not to be picky, but it's a flexplate, not a flywheel. No, I've never heard of something like that. Are you torquing the bolts are hand tightening?

Sorry, I now this is an old thread but I found it on a search, I have the same problem. Did you ever get this problem fixed? Was it the flexplate?