Suspected fuel pump issue

[tiprock]

Hi all,
My car will randomly die once in a while. But it will restart every time.
I’ve tried different batteries, alternators, ECUs, AFMs but will still get the random check engine light then rev drop to shut down aka randomly die.
I have a Carter fuel pump coming and I will try dropping the fuel tank for the 1st time.
My car is a gts swapped sr5 that I am at least the 3rd owner of.
I suspect maybe one of the previous owners hardwired the fuel pump check connector. I think I might have damaged the fuel pump when I put jumper cables the wrong way (super oof) when trying to jump start my friends car.
I have another 86 that I’ve had for 10+ years. And this car with the issue I’ve had for 8 years and I’ve never seen a problem like this before.
Any opinions or thoughts?
Thanks for reading and thanks in advance.

[davew7]

Check fuel pressure, should be around 38 psi. or fuel filter. Any problems at full throttle? But it sounds more like electrical. Possible loose connection? My fuel pump connection was loose right at the pump terminal on top of the tank. After repairing the wire, I added foam under the connection to prevent movement, from road impacts.

[tiprock]

thanks for responding
I wasn’t able to check exact fuel pressure because I broke the brass fitting the tester came with (oof).
but per the fsm if squeezing the fuel line from fuel filter to the fuel rail is alternative way to check fuel pressure (which I do feel pressure in the line when the engine is running).
as far as any issues during full throttle, I don’t really go to redline ever. I usually granny shift at about 6-6.5k.
tbh when my car cuts off I usually hit 6-6.5k to see if the engine will shut off again (which it doesn’t).
I did clean off some crud on some of the electrical fuel connectors in the trunk and re-routed the harness so it wasn’t under my spare tire. And I also re-did some misc Mickey Mouse wiring I’ve been too lazy in the past to re-do.
I’ve gone about 50 miles so far with no issues.
knock on wood. But I kind of don’t mind. What is life with out little challenges haha.
Once again thanks for responding.

[tiprock]

Looks like it was the efi main relay. so far I’ve done 300 miles and no random shut offs