UPDATE: I am still trying in my spare time to work on this GTP.
In the past week, I have had no trouble getting it started on a cold engine. Now, that has changed again, I tried to start it to move it into the garage and it would not start after 8 attempts. It cranked, but would not start, a few times it almost started. A few hours later, I tried starting it again and it started right up.
I had stopped at a shop few days ago about 5 miles away and talked with a mechanic who is recommended by some other local people I know. I explained to him what has been happening with the GTP. I told him I wanted to install the exhaust with the low mileage catalytic converter, and replace the rear valve cover gasket, and some other items.
I told him that I may be able to find what is causing the car to not start, and he said if I can't to call and make appointment and leave the car. He said he would check the fuel pressure gauge, and hook up a scan tool to check for codes, and he would check wires with a ohmmeter, he has done that before.
Anyways, last night, when I googled "3800 engine cranks but no start", one owner said he had a problem with the ICM (Ignition Control Module). He removed it and the underside was severely corroded. I had never had the coils or ICM removed from this car (actually never removed it from any GP I have owned)
When I did take off the ICM, it was severely corroded, both the module and the back plate. I removed the corrosion by had with various grades of sandpaper until the surface was shiny.
After putting on a coat of dielectric grease, and carefully putting everything back together, I turned the key to start and without hesitation, the engine started up.
I did not replace the ICM, I have other ones in the garage, but now I am not going to replace the one in the car.
I want to take it for a long drive and see if the boost gauge shows the level of boost as it was before.
I will report back again soon.
Pontiac owner since 1999, driven over 500,000 actual miles in Grand Prix's I have owned
2001 Pontiac GTP, silver (31,000 miles) too many mods to list, currently in storage
2001 Pontiac GTP, silver (98,000 miles) small turbo, built tranny, currently in storage
2002 Pontiac GT, 40th Anniv, dark cherry (273,000 miles) mild mods, daily driver
2002 Pontiac GTP, red (58,000 miles) strictly driven to car shows, currently in storage
2003 Pontiac GTP, LE, blue/black (187,000 miles) all stock, daily driver