I just bought a 2000 Grand prix GTP, it will start just fine but dies within a few seconds. I replaced the crank sensor behind the balancer and it did nothing. I read about the fuel pump resisitor causing the same problem and read to take out the relay and use a jumper wire to activate the fuel pump, if it stays running the resistor is the problem, well I did the jumper wire and nothing changed, it still starts then dies. I then thought of the security key shutoff, I have no flashing security light or anything to tell me that that is bad. I have a pk3 key and when I read how to relearn the key it says to leave the car on about 10 minutes and the security light will go out, mine never came on to go out. I need suggestions of anything else or something im overlooking. Much thanks.

While starting, can you keep it going by gently pushing the throttle down?

I have to keep jabbing the gas but yes it stays running that way. That'* why I ruled out security issues. Wouldnt it die no matter if you gas it or not of it was security related?

Depends on the security system. Old ones disabled the injectors, 95 disabled the fuel pump etc, but thing is, it wouldnt let the engine start or run.

If you can keep it runnin via the throttle, I'm suspecting the IAC valve sticking closed.

Just swapped the IAC with my SSEI and didn't change anything.

Check/clean the MAF sensor?

Exactly what I was thinking, I had a similar problem, and my MAF was actually fouled and would not read properly, it also had the tip come loose, I believe it is supposed to be removable to help clean the thermistors, but with mine the two little dots on each side that held the tip in place had been worn down, so sometimes the car would start fine, sometimes I had to pump the pedal, and that would spin that tip around enough to get me going, but it was sluggish!
If the thermistors get totally blocked the injectors will not fire.
Clean the MAF'* thermistors with MAF cleaner, be sure not to touch the thermistors.
Examine the tip of the MAF sensor, and see if it is coming off.
If you can get it idling decently, if possible I'd try to get a scantool hooked to it and see what the MAF is reading at idle.

Exactly Will. I experienced the same MAF tip issue a few months ago. Superglue seems to have fixed the problem so far.

I unplugged it to see if it did any change but it didn't. I'll take it off and replace it w another one I have and see if it helps. I also ordered a new key and am going to program that just cause I heard one guy say that his key was the reason it was stalling. If not the maf, what'* the next spot to check. Is there any way the jumper method to check the resistor may not prove that the resistor is actually bad?

I'd get rid of that tip, I super-glued mine, and in a week or so it was back to spinning, you may get lucky and it never come off again, but I think eventually it will separate again, hopefully not though.
I checked my scan tool with and without the tip, and there was no change in readings.
I eventually had to replace mine, as it was just a tiny bit off at idle, and that was causing a misfire at idle.