IDLEING PROBLEM PLEASE HELP!

[KC20DET]

Alright, well when im in idle my cars RPM jumps up around from 500-1500 rpm and it does this when i just start my car and at stops even when im rolling to a stop i throw it into neutral and it still revs up around 1500 rpm. When i first got the car it Idles nicely around 700 RPM without it jumping around. When it jumps up and down it shakes the car. Feels like my car is trying to breathe.

PS. Its a 91 240sx LE Oh yeah it works fine when driving through the gears. It just happens in Idle.

[sweets13]

what motor? if SR20 check for boost leaks, clean the MAF, IACV. Recently one of my couplers on the hotside going into the intercooler ripped and it was doing the same thing you're reporting. Coming to a stop just wanted to die, idled like crap.

[smokincoop]

check for intake leaks. When was the last time you changed fuel filter or did upper intake cleaning?

[KC20DET]

im not sure i just bought the car like a month ago. and its running a KA. Do you think a simple tune up with spark plugs and distributor and wires could do it? im gonna check with the Intake but it doesnt seem to leak. Im not planning to spend alot on fixing it i just need it to last awhile longer. im planning to get a sr in it by early next year.