I have a 1993 trans am and I just installed a 2 1/2" True dual set up w/ bullets dumped before the axle, and new poly motor and trans mounts. The problem i,m having is there is a really strong virbration right at 2000 RPMs. It,s smooth from idle all the way to 1900 RPMs and smooth from 2100 all the way to 6000 RPM, but the really vibrates strong exactly at 2000 RPM. Please Help!!!

 

Check to make sure no exhaust components are rubbing against the body/cross member(s).

Also, does it do it in neutral/park, while driving, or both?

What specifically vibrates?

 

Id say its just the new mounts You get more vibs out of them. Over time you will notice it less

 

It does it while driving and in park/neutral!!!

 

most likely polly mounts. I'm going back to rubber engine mounts and suspention bushings. polly realy transfers every little vibration or ripple in the road not to mention the pot holes. I hate it for a non track car.