Rough Idle after sitting

[mtnxr]

I have a 2000 GMC 5.3 and it starts and runs fine when either fully cold or hot. The problem occurs when I drive it and park for an hour or so and go to start it...sometimes it just idles rough for about 10 to 20 seconds and sometimes it doesn't really want to start. I am thinking it must be a tempature sensor or something. Any help would be appreciated.

[Shaners]

There seems to have been a rash of fuel pressure regulators that have caused starting problems in the past. Usually it's a long cranking period before it fires, but I wonder if yours might be starting to show some signs of trouble... (just a guess).

[stef8]

I agree, definitely fuel pressure regulator malfonction. I changed mine last fall and I had the exact same symptoms. If you want to know if yours is bad, just remove the vacuum tube at the pressure regulator, if fuel is present in the tube, you just found the problem.

 

Good luck!

 

Stef

[mtnxr]

THanks, I will check the regulator. Seems strange that it starts fine in the morning when its cold.

[mtnxr]

Thanks guys, the pressure regulator was the problem.