A couple of months ago, my Tahoe started running rough at cold start in the mornings, but runs fine once warmed up. The problem is getting a little worse, and having to give it a little gas in the mornings to get to a smooth idle, but the rough idle still goes completely away when warm. This only happens in the mornings. I've got about 118k miles on this baby, and since I hadn't replaced plugs and wires, I went ahead and took of that first. After replacing plugs and wires, I'm still having the same problem. I prefer to do the research myself and try to fix the problem without having to go to a shop, and get a little education in doing so. Can anyone give me some advise on what to look for next or other possible culprits?

I'd appreciate any help or advise anyone can provide.

Thanks everyone!

 

Check fuel pump pressure and if OK, run some Techron thru it. My $.02.

 

Thanks for the advise. I hooked up a MasterTech scanner, and read codes PO171 and PO174 (lean fuel mixture) along with PO300 (random misfire); I've read through other posts, and this combination seems to be a sure bet that intake gaskets are leaking when cold. Also found that carbon build up in throttle body may also affect cold start. I'm going to try to clean up the TB this weekend; hopefully this is an easy fix.