The car i`m using at the moment is a 95 wrx, when the car is at idle it seems a bit rough, revs rise and fall between 900 and 1200 rpm and when starting from cold the revs take a while to build up, performance seems unaffected at higher speeds. I intend to change the plugs to start with, any other ideas as to what might be the problem would be appreciated.

 

Moz,

Is the 'check engine' light on?

My STI did this. Idle was terrible. Called out the AA who could find nothing. Was just about to book it in at the garage when the AA man heard a tiny gushing noise. There are a couple of little rubber pipes near the front suspension mount (drivers side, sorry to the techies, I don't know what pipes they are). One had come adrift just a fraction. Pushed it slightly back on and hey presto. Problem cured.

Worth checking.

If not. I hope it will not be too serious.

CB

 

Moz,first thing to check would be the idle speed control valve,located on th n/s of the inlet manifold.Remove the four bolts and take the two screws out of the top of the unit.Clean out the carbon from the valve,refit the top section in the same place,but leave the screws loose(just nipped)Refit the ISC valve.Start the car and let it warm up.You may have to adjust the top section fractionally to get the idle right.Sub dealers use the Select Monitor to set these up.Should sort the problem.ISC valves get coked over a period of time and need cleaning.Let me know if this resolves the problem.

 

Moz,

YOU MUST have a possum link then!!

Scatman.