Pirrex

I bought a 944S a while ago, and it has one annoying problem; for the first few minutes when the engine is cold, the engine gets really close to stalling when releasing the throttle with the clutch in. For example when crawling in traffic and i have to keep pressing the clutch and throttle idle, it goes down to like 400rpm, up to 1200 before it settles on 900.

This is not only annoying, but makes it really difficult to drive slowly when cold. What could cause this? I bought the car with a failed cam belt, installed the cam gear in the same place but with a decked head. Could too much advance cam timing cause this or something else? When the engine is hot it runs perfect.

plumbum

I would check the idle speed (Clarke garage has a write up on the procedure) also a falty idle control solenoid and vacuum leaks could cause the same issues.

I am guessing when warm everything is fine?

Pirrex

I will check the idle speed procedure. Any way to check the ISV? Doubt it's a vacuum leak as i had to remove all hoses when i had my intake manifold out, and behaved the same before and after. Yes, after the engine gets warm it runs perfect. It couldnt possibly be due to incorrent cam timing, as i have had the cams out, but the cam gear SHOULD be in the same timing as before. I bought the car with a cam belt failure, and don't know how it was earlier.