Hesitation During Cold Start

[gptahoe]

[/COLOR]Yea my check engine light is on. I did take it to 2 shops to get the code scanned but their scanner didnt turn on. Ill change the cig fuse and see if that will help so i can scan the check engine light.

 

[dwmmatt23]

It was 45 this morning when i started it and it stumbled as usual but hen for the first time this year it through a p0300 and didnt clear itself, scanned it and cleared code and never came back so i gotta push myself to get the time to try changing out manifold gasket now.

 

[bottomline2000]

Did you notice any regained MPG when it was replaced? Just trying to find the time to do mine, would be nice if it still had a warranty

I can't say I noticed the fuel mileage difference only because I took it to the shop within 2-3 days after it started. It's been some years since the gasket was replaced and it hasn't happened since.

 

[AZ-Yukon]

I've had the same problem for the past 2 or 3 winters, with the exception that it doesn't die. The idle is just all over the place until it warms up. The check engine light will come on for a few days, then go off and back on again. If I recall correctly, I was getting lean mixture error codes. I've cleaned the air intake with no success as well as replaced the mass air flow sensor and O2 sensors. I need to replace the oil pressure sensor as it has gone out. If the Yukon is like the vette (same part is used on the 2003 5.3L Yukon as a 2000 vette) I will have to take the intake off to get to the oil pressure sensor anyway. I'm hoping the intake manifold gasket is my problem. Two birds with one stone!