SpunMufflerBearings

I know its a GMC, but its the same truck as the chevy's, just wanted to see if anyone has had this problem. My truck only recently started doing this... When I go out to start my truck in the morning for work, I turn the key and the truck starts for about 2 seconds then shuts off. I turn the key off and start it again... same thing. I give it gas to keep it running the next time and it stays running but it runs like crap and if i let off the gas, it will idle to about 100 rpms, then die.

The strange thing is that it only does this SOME TIMES. I have yet to see a pattern. Sometimes It wont do it in the morning, but it will do it after i get home from work and I shut it off then get back in it 10 min later and try to start it.

ANY IDEAS?? My first thought is either fuel pump, or electrical. The truck seems like it has some electrical issues considering i've gone through 3 altenators, but this last one seems to be running strong. my dash lights have a slight flicker in them when I drive on the highway. let me know if you have run into this. Thanks guys.

SpunMufflerBearings

Just so everyone knows. The truck has 212,000 miles. And it just died on me as I was pulling into my work's parking lot. There is absolutely NO power to anythign now... I just rolled into a spot and no lights will even turn on when I turn the key off and on. some of my guages are still stuck up. I didnt know I could have 20 psi of oil pressure when the truck is off....

StanSuarez

After reading your first post, I was about to suggest you check the fuel pump since I had a similar problem earlier this year with my truck and it was the fuel pump that was causing the trouble.

However when I read your 2nd post, then I'll have be Captain Obvious here and have you check your electrical systems first. You might have a short circuit somewhere and blew out a few of your fuses.