I don't know if you found the solution to your problem. But i registered to try and help you or anyone with a GTP that may have this problem. I ran into this last year with my wifes 2000GTP. On the GTP there is a resistor that is for the fuel system that only kicks in when the supercharger is used. However it will cause the engine to turn on and run for a few seconds and then shuts off. It drove me and a mechanic friend nuts trying to figure out what was going on with it. We checked the fuel pump and pressure reg etc. Found no problems. We didnt have a manual handy either. He went to work the next day and looked up the wiring diagram for the GTP and found the resistor. I physically checked it and it was damaged (cracked off part of the porcelin). Replaced it and has run great since. The resistor is located on the frame by the front passenger wheel. It was a white horseshoe shaped part with a 2 pin connector. I think it cost about $50 from the dealer. Autozone etc. didnt have it. Hope that helps someone. I know it drove me crazy for a couple days trying to figure out what was wrong.
