Z44

My 92 SC 400 idels kinda high when in nutrual position and recently started idiling irratically. When in nutral, reves up and down, but not steadly. Could it be the Air Idel Control or Mass Air Sensor or any other sensors. I've notice on this site lots of ideling problems with SC 400. I had mechanic recent replace, plugs, coil pack, battery, time belt, alternator. Runs great with the execption of idel problem. Prior to mechanic, it was ideling really low, would also die, had to keep my foot on gas peddal, but once on the highway would do great, on Stop sign would die. And by the way no "check engine light" Please help

6SOARER

iTrader: (20)

could be your IACV. Try cleaning it out, also check for disconnected vacuum lines. Big vacuum leaks can cause high and sometimes unstable idle..

SHOLEXMAN

If it is surging put some pliers on the main intake hose going to the IACV. That is located in the front of the motor on top. If the surging stops when you clamp that hose down your IACV is stuck open. Clean the dowel pin that it rides on and then if it still sticks you need to buy another IACV. Good luck!

GSLEX99

Man I'm having somewhat the same problem in my 92 sc400, but mine is idling mad low and it sounds like it has cams but it does not. Idk what to do. sorry just looking around cl and saw your post so just thought i would share my problem too.