Cold start issue

[old coot]

I have a 2002 1500 with the 5.7L V8. It just started acting up when starting on cooler mornings. When it starts the engine will surge 3 to 500 rpms. It struggles to stay running while this is happening. If it stalls it will restart but continues surging. I can keep it running until it warms up and the issue go's away and the truck runs great. This typically happens when the ambient temperature is below 40 to 45 degrees. It never throws a code when this happens. Otherwise the truck starts and runs great. Any ideas where the problem in coming from?

 

[jws123]

Clean your throttle body could be sticking The IAC is built into the throttle body its possible you need to replace it. Other things to check test your battery and check fuel pressure. Side note 2002 didnt have a 5.7 so I assuem you have a 03+ however if you do have a 2002 thats a 2nd gen with likely a 5.9 and is way diffrent.

 

[old coot]

Thanks and yes it is 5.9L. I just didn't proof read the post. Took your advice, cleaned throttle body and replaced IAC. Seems to have cured the problem.

 

[old coot]

I thought replacing the IAC valve fixed the starting issue. This morning the issue returned. Not sure what ambient temperature has to do with it but it does have an effect on starting. This morning temperature was 43 degrees and it's not raining but high moisture content in the air. Not sure where to look next. Anyone have suggestions?