Stalling on start up

[RustyPile]

I'll address your first paragraph..

I'm pretty close to being a "Mr. Goodwrench", as I'm a GM trained Drivability Technician. Engine stalling and low idle speed is a very common complaint. I've had my hands on hundreds of vehicles with that issue.. But I must tell you, for that one complaint, there are numerous solutions.. Stuck EGR valve, Stuck or dirty IAC valve. Defective logics in the computer, faulty or missing RPM signal, Coolant temp sensor... The list goes on and on..

Within your dissertation, not one word about a trouble code or check engine light being on. A scan tool, a code chart, and a troubleshooting flow chart are aids for deciphering those items.. Here's a link to an example of a flow chart..

https://www.bing.com/search?q=GM+tro...ANAB01&PC=LCTS

As to your 3rd paragraph: Since you don't have much faith in check engine lights and trouble code accuracy (probably due to your lack of knowledge of how the system works), that's about all I can do towards helping you..