I have a 92 Camaro RS, 305 TBI, T5. Ever since I bought it about three years ago it has had a vibration. Its a small vibration at idle and gets worse as it rises to 2500 to 3000 then tapers off a little bit beyond that. It does it any time, while driving, while in neutral, with the clutch is pushed in, no matter what it vibrates.
I have changed U-joints, trans and motor mounts (Energy Suspension), and full engine tune up (runs great).
I took the flywheel out and had it turned, it wasn't warped at all. When I put the flywheel back in I ran the engine without the trans or clutch hooked up, No vibration. Put trans back in, vibration came back. So I unbolted the trans, and bolted on just the pressure plate without the clutch, No vibration. I bolted up the trans without the clutch and pressure plate, vibration back. It has a Centerforce clutch so I got on their web site and it said the bell housing could be off center, so I checked it and it was at 4.5, the site said no more than 5. The only thing I have bought but not installed yet is the pilot bearing. Sorry this is so long, but I am out of ideas.

 

when you replace the pilot bearing check the end of the input shaft for wear and the splines. slide the clutch disc on the input shaft to check for wear. also look at the engine and tranny mounts. make sure the exhaust isn't hitting anywhere.

 

Is your trans mount good?

 

Ran out in the garage real fast, exhaust isn't hitting anywhere, splines don't look worn, clutch disk doesn't seem to have any play when slid on. Pilot bearing slides on smooth doesn't seem like theres any wear. The trans shaft its self doesn't seem to have any play either.

 

Engine and trans mounts brand new.

 

how were you supporting the engine with the tranny out?

 

Just the engine mounts.