Idle hunting issue

[pwpanas]

Originally Posted by Durandal

Yah I've been leaning towards a small boost leak. I had a boost leak awhile ago where one of the accordion style rubber pipes above the turbos was loose but I fixed that.

I had my exhaust from the turbo manifold back removed last year to look at removing the stock cats but didn't do anything with it and just put it back on. I don't think an exhaust leak there would be causing this though. I guess I'll rig up one of those homemade boost leak testers and check my IAC just to be sure.

The thing is if I keep my foot steady on the pedal under boost, my boost gauge stays constant and doesn't drop off.

*edit: Did another visual inspection today and found a couple hoses with small cracks on the ends of them at the EGCV VSV and a some above the turbos. Going to look at replacing them although they don't seem to be leaking.

I give the car a cold start and it idles at around 900 which is good, but after it warms up the idle goes up to 1100-1200. I take it for a drive to test my boost pressures and am getting around 8 psi from turbo1 until turbo2 kicks in at 4000 RPM and my boost pressure goes up to 14 psi.

I did add some fuel injection cleaner last time I got gas but that wouldn't increase my idle 200 RPM would it?

Agreed fuel injector cleaner wouldn't cause it. However, it wouldn't take more than a very small-sized hole to create enough of a boost leak to raise your idle. However, that small sized hole wouldn't necessarily be big enough to cause a noticeable a drop in boost pressure on the high end (total air volume is many times more under load and higher rpm while boosting).