Won't idle when cold

[Mattchev]

My 00 silverado 2500 won't idle when it's cold. It starts fine but when the rpm drop to idle it dies unless I hit the gas and then it will jump up for a few seconds and then down and die or I can hold it at 1000 rpm until it warms up a bit and then it wil idle rough until it's right up to operating temp. Once it's warmed right up it runs great. Anyone have any ideas where to start?

[txab]

Check intake gaskets for starters

[Silverado4x4]

Start the motor and take some carb cleaner and spray around the intake gaskets to the head and see if the idle changes if it does then you found the problem, when was the last time you cleaned the throttle body? Any codes?

[Mattchev]

I have never cleaned the throttle body. I just bought it but when I unplug the mass air flow sensor it idles good and it drives ok but lacks power at highway speeds. I haven't had time to try spraying starter fluid around the intake gaskets yet but I'm going to try that this weekend

[HawkScot]

I have never cleaned the throttle body. I just bought it but when I unplug the mass air flow sensor it idles good and it drives ok but lacks power at highway speeds. I haven't had time to try spraying starter fluid around the intake gaskets yet but I'm going to try that this weekend

 

Not sure I would be using starter fluid, that can cause problems if you are not careful..

[txab]

Yep. Clean the throttle body and the mass airflow sensor also

[Mattchev]

I cleaned the maf sensor and at first it seemed better but then got worse. Also I noticed I'm missing one hose clamp on the air intake hose. Could it be getting to much air through that connection?

[txab]

Any unmetered air can throw things off. You did use MAF cleaner right?

[Mattchev]

No rubbing alchohol

[Mattchev]

I replaced the maf sensor and it ran great for about 10 min and then the idle went a little rough. Not like before but kind of an inconsistent idle speed. Intake manifold gaskets are good. I'm wondering if I have to reset anything on the computer now?