I have a 90 240sx. The engine is in pretty good shape but my idle is jacked up. It'll be at 1200 once started then it casually makes its way to 2000 then backs way down to 1000 and repeats the process. Sometimes it goes quicker than others. I checked my MAF and its clean and fine. Please help and tell me what it could be. Thanks

 

check your timing,idle control valve,dist. cap&rotor