Well I have a 97 Turbo LS and I was running with the pcv valve disconected (for my wastegate) and It idled normal, than the other day I istalled a vaccum manifold and hooked my pcv back up. At first my idle was just alittle high 900-1100 RPMs than today when I went to school my idle starting jumping from 2000 down to 900 and than back up to 2k again. but somtimes it would stay at 2k for awhile than drop down and somtimes it would go from 2k to 900 and back without stopping. Oh yeah and as soon as it started jumping back and forth I got a check engine light. Does anyone know what this could be. I checked all my connections, and vaccum lines. I don't think its my idle screw cause I have a CEL I think it might have somthing to do with my IAC valve. anyhelp is appriacated!

 

Nevermind It was my pcv.

 

Well if it comes back, I had the same thing with my idle jumping and it was my idle air controle valve.

 

I just bought a 5 speed 4door 98 gsr. I have a few questions since im a newby. My engine light comes on even after the IAC has been adjusted. If i dont push in the cluth when i slow down the car will buck violently. Gas milege is ridiculous what could it be? I just took it up to get it fixed and it cost me 900 bucks. It only has 113,000 miles on it and it sounds great and looks great but it runs poorly. Its starting to smoke. when i slow down i have to push in the cluth or it will jump violently. IS the smoke from the engine coming from the clutch? PLEASE PLEASE HELP ME!

 

Have you checked all of your vaccum lines for leaks? In my case my pcv valve was busted causing a huge vacuum leak that made my car run like crap! Is the smoke coming out of your exhuast, or your Engine bay?