Alright, so here is one that puzzles me. I have a GTP with the L32

My car will start completely normal from a cold start but once the car gets up to operating temp the car will turn over, start,and then die almost immediately after it starts up. To get the car to stay on we would have to disconnect the egr sensor and then unplug the vacuum line from the brake booster on top of the supercharger and then quickly plug it back in once the car was running for a few seconds. The important part of all of this is that once the car stays started the car runs completely fine, idles fine and has full power, boost, everything.

At first we thought the egr was stuck completely open even though most times the car can overcome it. We decided to rule it out anyways and took it out of the car (yes we covered the remaining holes). Tried to start the car again, it would start and then die again right after it starts up. A scanner showed the car has the vacuum it should. We hooked a tester light up and got spark, checked to see if an injector was leaking and made sure the fuel pressure was correct and it was. We also cleaned the map sensor and still the car would start and then die immediately. So we disconnected the throttle body sensor with the key to full accessory and threw the car into reduced power mode, after which the car started right up. It had a rough idle but the car started every time we tried it while in reduced power mode (with the brake booster line connected).

Any ideas of where to look next?

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2004 Grand Prix GTP
FWI | HP Tuner | 1.9 Rockers | Headers | 3.5 Pulley | 97-03 Control Arms w/GMPP sway bar|

Fuel pressure doesn't mean volume. Pressure is good, but if you've got a blockage somewhere, or a weak pump once warmed up, it could be a concern. What happens if you ONLY disconnect the EGR?

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One Big Ass Mistake America

There is no more egr and the car does the same thing as when the egr was connected or not. And if the fuel pump was bad once we get the car started wouldn't there be an issue with the car running?

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2004 Grand Prix GTP
FWI | HP Tuner | 1.9 Rockers | Headers | 3.5 Pulley | 97-03 Control Arms w/GMPP sway bar|

It could depend. But, after I posted that, I got to thinking, and the fuel pump is likely NOT suspect, though it wouldn't hurt to check it. You would be right, though, that a weak pump once warm SHOULD give trouble at high load, and it sounds like yours doesn't. It could still be a crank sensor. My dad had this happen on his LeSabre (L36) where once up to temp, the sensor would fail, and there'd be no spark. Did it twice, he replaced it, and it was gone. It threw no codes.

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One Big Ass Mistake America

Swapped the throttle body for my buddy's off his 04 and had the same starting issue. We deduced the problem to the cam sensor getting heatsoaked while the car is warm. Scanning the car while it was running from a cold start showed no problems when we went through the log, scanned the car from a warm start, all the sensors the scan read were fine and working properly, the only sensors we couldn't scan were the cam and crank sensors. Since the car start and then immediately dies we are pointing more towards the cam sensor. Gonna probe the cam sensor tonight after I get off work and if thats it, 38 bucks at advance and i'm all good. *crosses fingers*

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2004 Grand Prix GTP
FWI | HP Tuner | 1.9 Rockers | Headers | 3.5 Pulley | 97-03 Control Arms w/GMPP sway bar|

Cam sensor? I wouldn't suspect a cam sensor. I'd be more suspect the wiring for it or the crank sensor itself. Problem is, I don't know how to test that stuff.

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One Big Ass Mistake America

take two pins be it needles or a paper clip trimmed and backprobe the electrical connectors and then hook it up to an multimeter and check the voltages...

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180 T stat, HV3, Wizaired Intake, GMPP Exhaust, Speed Daddy Headers, 1.9 Yella Terra Rockers, Eibach Springs on KYB AGX Struts, Custom LED interior light switches, BBEngineering.com 6 Pod Cluster, Poly Mounts and Bushings, Mild Tune, Gen 3 Coming Soon with L26 block, HPTuner

Now this is a shot in the dark but thought I would see what someone else thought..

The plugs in the car are complete shit right now due to oil fouling because the valve seals weren't pushed down all the way. Could it be possible that when the car is cold the plugs are cold and are able to make a more reasonable spark and when the car gets up to operating temp the plugs are able to keep the car alive with no problems but once you turn the car off the plugs are having a problem producing the spark needed to turn over due to them being so fouled and now their hot?

Just a shot in the dark but figured id throw it out there before we start replacing the cam and crank sensors.

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GPDIY - For All Your DIY Needs
VS CAM|3.4|HEADERS|FWI|42.5#|HPT|6000k LOWS|8000k FOGS|

If they're junk, replace them. Rather spend $12 on something that needs to be replaced anyways, than to spend time and money needlessly.

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One Big Ass Mistake America