Hi, my name is scott and I'm new to this forum. I have an 03 silverado 1/2 ton, 5.3L with 150k miles. I've noticed when it gets cold (under 30) it's always ran a little rough until it warms up, but this year, and especially the past month, it's gotten progressively worse and finally throwing these codes. At cold start, engine start fine and idles good for 5-10 seconds, then begins running/idleing very rough. The warmer the engine gets, the better the idle, but when cold enough out (0 or lower up here in lovely MN) the idle doesn't really get better and at stop signs/etc the engine wants to jump. I can reset the code and if the engine is warm enough, it won't come back until the next time it's cold. From what I've been reading, sounds like a manifold gasket leak (warms, expands, seals) but am just wondering if anyone else has had the same cold weather issue and if this solved the issue (haven't had luck finding a leak yet). Any help would be appreciated!

 

you need intake gaskets. i think those are lean codes right? been a gm tech for 4 years and i've probably done about a dozen of them.