View Full Version : Odd Vibrations in Drive and Reverse

05-06-2007, 05:57 PM
My 1990 AOD SC is acting really odd. It idles a little rough (evan sounds a little like it's missing. But when i put it into drive or reverse the RPMs drop a little bit and the car starts to vibrate like an old muscle car. It still has pretty strong pick-up and runs decent it just has this weird vibration.

And after driving it a while when i come to a stop light, my rpms drop a bit and it vibrates rough. Anyone have any idea what that could mean off the top of their heads?

05-06-2007, 06:07 PM
Had similar problem with my 92 SC. Rough idle. Turned out to be issues with worn out motor mounts and tired bearings in belt tensioners. I was told the engine sensors interpret the vibration as engine knock and retards the ignition timing causing rough idle. Had it all replaced (not cheap) and fixed the problem. Hope this helps. Good luck.