Hey guys I’m looking for little help. I posted this in the tech and civic forum and i didn’t get any answer may be some in here can help me out. I just picked up a 92Si a few weeks ago. I traded my Acura legend for it. All and all the car pulls hard and it’s a nice car. It has a few visible performance mods headers, CAI, and cat back. But there is one problem, when the car idles it bounces from 1000rpm to 2000rpm back and forth. Does any one know what could be causing it to idle that way? The guy I got the car from bought it from this guy in NY and he has no idea if he did any motor work to it. Any info will be greatly appreciated

 

possible vacume leak, throttle body gasket leak, bad IAC can do it...

 

Check how tight the throttle cable is, and check the fast idle valve (might need to be cleaned).