2000 Sierra rough idle when slightly warm

[jfalbe]

My 2000 Sierra will start and run fine when cold. It normally starts and runs fine if its up to operating temp and then started immediately. The problem comes when I get it to normal temp and then let it sit for 30-60 minutes. Then is it starts it run very rough for a little bit, if I can keep it running, it'll straighten up and run perfect. If not, it might die and have to crank on it for a little bit to start it back up. I've had suggestions of a new idle air control valve and flashing the computer, neither of which makes sense to me. Any ideas? Other threads lead me to the fuel pressure regulator which I plan on investigating but other ideas appreciated.

Thx,
-J

[Jeremy-WI]

Sounds like a fuel pressure regulator to me, or a strong possibility

[GMCTech]

Both are possibilities.

To be certain you'll have to hook it up to a scan tool that allows you watch data. And especilly check IAC performance and EGR performance, as well as misfires.

Hope this helps.

[jfalbe]

Originally Posted by GMCTech

Both are possibilities.

To be certain you'll have to hook it up to a scan tool that allows you watch data. And especilly check IAC performance and EGR performance, as well as misfires.

Hope this helps.

I have used the scan tool and the IAC functions fine. The mechanic thought that it might be sticking on startup though. Going to replace the fuel pressure regulator after it comes in (special order). Thanks for the info though.

[jfalbe]

FYI, the fuel pressure regulator fixed my problem.
Thanks,