I just purchased my 2002 Tahoe a few weeks ago and have done a majority of the main services I believe it needed. Changed the rear diff fluid, new transmission filter and fluid, front diff fluid, new air filter, new cabin air filter, new rear rotors, new rear pads, adjusted the E brake, oil change and filter. I've noticed that when she sits for 24 hours or longer on a cold ( California ) morning the engine will shake quite a bit almost like a piston is misfiring but once its warmed up a few minutes I don't notice the problem. Any suggestions? I was thinking it could be injectors/spark plugs/ or spark plug wires with a bad connection. It doesn't throw any codes or service lights. Seems like its spuddering, closest thing I've experienced was when I had a toyota with a 22re engine the valves needed to be adjusted. But I'm here for any good suggestions.

 

Does it throw any codes with a scanner? If it's cold, and doing this could be running lean. Some things to think about leaking intake manifold gaskets plugged fuel filter or bad fuel pressure regulator. Start with a scan first.

How many miles on it? Don't forget to change the transfer case fluid. That is on my to-do list on my 2002 Tahoe.

 

It wasn't throwing any codes, but this morning when I started her up, she did the same thing and the "Service Engine Soon." after she warmed up, the light turned off, but I do know i've got leaking manifold gaskets on top. I plan to change the manifold gasket, and I'm going to try and scan it while its starting up to see if it'll flag a code.