I have a 2004 LS and it idles great, drives great, but then after I drive it some where and it sits for more than a few minutes, it has trouble starting. Is it flooding itself? Take 2-3 tries then runs funny for a couple seconds then runs just fine out on the road. No putting when idling and no missing when revved up. I've ran sea foam through the fuel tank, no help. No service engine soon light either. Also if I turn it off after driving, then start it back up within a minute or so it fires right up. Anyone have any suggestions on what this could be? I just don't want to replace something that doesn't need to be replaced.
Thanks! Pat

 

To me, it sounds like your car is losing the prime in the fuel line. If you try to start it right away after a trip you still have fuel in the line. After a few minutes the fuel would be displaced by air. What about overnight? Is it hard to start in the morning? I'm guessing that it is. Start by looking/smelling for fuel that has leaked out of the system. Good luck.

 

I bet you have a bad fuel pressure regulator. Very common problem on a lot of gm's. Pull the vacuum hose off of it and give it a sniff, if it smells like fuel then that's your problem

 

Thanks to both of you guys, I just read that when the FUEL PRESSURE REGULATOR on the 3.4l fails, it will cause a hard start, long crank time, and running rough when started. It also causes poor fuel economy, wonderful since gas is almost $3 a gallon. Now I know FOR SURE that it's the regulator and not the fuel pump thank God.

 

Nice cars by the way, hope to upgrade from this slug soon.