Wondering if anyone else has had this issue. I'll start from the beginning as to narrow down as many things as possible.

So around the end of October I was driving down the road and all of a sudden the power cut and the motor just shut off. After I coasted into a parking lot I cycled the key and noticed the fuel pump not engaging and the car would just go click. Posted a thread before when this happened to see what was up but figured I'd upgrade the parts anyway.

Figured it was the fuel pump that finally crapped out after 90k some miles so I upgraded the stock fuel pump and bumped the injectors up to 60 lbs from 42 lbs while I was at it. Found out the stock pump was still good too, went to start the car and nope, same click.

Went through as much of the electrical as we could and found all fuses and relays to be fine. When we hotwired the connection for the fuel pump where the relay switch is, with a wire to a ground, the fuel pump and electric water pump would go on fine. Found out the PCM was shot. Replaced the PCM and found out I actually had the wrong PCM in there to begin with. Bought the car used so I guess that explained the electrical hiccups I had every now and then. Everything seemed to be fine for a half hour or so.

While running the car and trying to tune it we were still getting lean codes from the MAF. Car actually shut off a couple times. My low oil level warning was on as well even though my oil level was fine. Drove the car around some more, wasn't running very smooth, then after about 10 minutes shut off then wouldn't start again.

It would crank, fire up than shut right off. Finally for some reason my tuner, Mike fired the car back up after waiting a few minutes and kept the key on the cranking position. The car stayed on and ran fine, no bucks, no rough idle (aside from the usual big cam idle) etc. Had to drive the car back home while I held the key on the cranking position. He said it was definitely the ignition and I should replace the ignition switch. Figured, finally the problem is solved.....

Nope. Got the new ignition switch, installed it, same problem. Have to keep the key on the starting position for the car to run, when I back off a bit to the on position the car starts to shut off. My tuner is coming down this weekend to start diagnosing the problem. He says 12volts is not going to where it should and that there is some wire not doing it. We're pretty sure its between the ignition switch and the relays/fusebox, etc. Has anyone ever had an issue like this?

Just to recap from a previous thread, car is anything but stock. 427 stroker, battery relocation, etc. Any other thoughts would be appreciated. As I said, been dealing with this since October so I'm hoping it is a simple fix so I can get back to driving. Sorry for another long post but I did try to sum it up as best as I could. Thanks.

 

Fuel pump relay.

 

This might help in your troubleshooting:

 

Thanks for the diagram. This should help us this weekend. Sure has been one hell of an ordeal. One electrical thing after the other. Thought it would be solved with a new PCM cause that was the first issue screwing with the fuel pump and water pump. That got fixed, but now its ignition related. Replaced the ignition switch figuring that had to be it, but wow...

Never thought this would happen. I don't think I've ever seen it where you actually have to hold the key on the cranking position just to keep the car running fine, then have the car shut off when you back off to the on position. Car cranks and fires up and the starter even disengages, but you have to have the key on the crank position. Weird stuff man...