08 Grand Prix, 3.8l Series III V6, around 206,000mi on the clock.
Here's what I'm encountering, I'm hoping someone here can point me in the right direction as I've searched all over the internet and tried everything I've found and can think of, and gotten nowhere. Around March/April of last year, I noticed the car running pretty poorly, so we changed the plugs and wires. Then the alternator and starter decided to die at the same time a few weeks later. Got that cleared up, then parked it to take a ride from GA to CT in our other vehicles. We came back home, it started a few times, but would just...die. Managed to move it from one side of the yard to the other in Late July/August, and haven't been able to start it since. At first it wouldn't even try to crank, so I figured it was time for a new crank sensor. Changed that, and the cam sensor, and now it'll try to crank, but no fire. Took a look at the ignition wires, and it turns out they were defective, so we got them replaced. No progress. Figured it might be the coils, changed them, no progress. Finally pulled the plugs out, and they all had one weird burn mark in the exact same spot, so we got them replaced. New ignition module to be safe. Checked all the fuses, relays, none were broken, but replaced a couple nasty looking fuses anyway. Still nothing. Even changed out the wiring harness that plugs into the ignition module. Still nothing. Throughout all this we've also replaced both batteries cables with ACDelco factory replacement cables. The car still will not start, but everything else is working as normal. Found a video with the same issue, the guy tightened the grounding bolts in the fuse box and it worked, so we tried that. Still nothing. Any insight or help in this matter would be exceedingly appreciated.
List of new parts for reference: New alternator, starter, battery cables, ICM connector, ACDelco plugs, new coils, new wires, new ignition module, new crank and cam sensors.
Battery is fairly new, and I don't believe that's the cause of the issue. We've tested spark, and we get nothing from testing the wire, and nothing from testing the plugs against a ground. Just no fire whatsoever.
