help rough idle

I get rough idling on my 95 SC2 when I shift into reverse. It's a
loud vibrating sound, but quiets down after its warmed up or 10 minutes of driving. Tuned up about 30k ago so do I need another tune-up or
something?

auto or manual trany?
any 'slamming' into reverse?
any 'slamming' into drive?
does this only happen after shifting into revesre?
ever had the ECT sensor replaced?
ever have problems with the motor mounts?

automatic, it slamms into reverse. I never had the ect sensor replaced or checked the motor mounts.

does this sound like your problem?

http://www.saturnfans.com/forums/showthread.php3?s=&threadid=23670

and heres a how-to for the ECT

http://www.saturnfans.com/forums/showthread.php3?s=&threadid=24003