weird idel when cold and MPG gauge Reading 5mpg when still?

[formula driver]

I start my car up and the idel bounces for a few seconds until it warms up just a bit and it only does it when my car is ice cold. It did it tonight and the car stalled. I can Idel while Im driving and the MPG gauge is fine but when I come to a complete stop the MPG gauge reads 5 MPG when Im at idel. Have any clues whats wrong? Im thinking maybe CSV or the ECU. Its got a remanufactered ECU. Thanks for any help...

[jlevie]

This could be any of a number of things, but the first though that comes to mind would be a small intake leak. The engine needs a richer mixture on a clod start and even a small intake leak may lean it out enough to cause problems. Probably also be a good idea to clean the ICV since it could be sticking when cold.

Note that when looking for a small intake leak you really need to pull the intake boot. Cracks that can't be readily seen become very apparent with the boot in you hands.

[O 16581 72452 5]

Search for "ICV" or "IACV"

[formula driver]

Bump, any more ideas? The car has a new ICV....

Could it be the cold start valve? Or maybe the AFM?

[euroshark]

I suppose it could be the cold start valve. Unplug it and see if the problem is still there. The AFM really won't cause an issue like this, but you could try adjusting the mixture a little richer (usually a 5mm allen head adjustment screw - richer is clockwise).

O 16581 72452 5 - Have you tried the Extra Stout? Oh boy, so much better than the regular Draught imo, almost like a Russian Imperial Stout actually! :drink:

[dude8383]

where is this cold start valve?

[euroshark]

I don't know on the M42, but it's usually blue, has a black fuel line going to it, and a standard injector plug (may be blue), and it's ON the intake manifold. It might be under the throttle body, or just somewhere on the underside of the intake manifold.

[formula driver]

I found a fair sized hole in my air filter, its a crap filter anyway. Do you think this could be cause of the problem? It would idel weird if it was getting to much cold air wouldnt it? Its starting to get worse, it sputters now until its warn and its ideling at 1200 or so all the time...