I bought a 2003 f150 5.4 engine from a guy who could't get it started. He was running down the road and it quit. Here is what I have done. I put a crankshaft and camshaft sensor in. The fuel pump engages, put there is not fuel pressure. The gauge won't even register. The truck will finally kick in and run about 500 rpm and maybe 1000 with the pedal all the way down. Lift the pedal and it dies. It runs rough that whole time.
I have read about the pcm or the fuel relay but the fuel pump engages so didn't know if that would happen if those are out. The integral switch seams to be working not sure how to tell for sure? Another guy checked it and said it was fine.
What should I do next?

 

Haven't you learned anything yet?
Sell the truck to the next sucker like the last guy did.
.
Kidding aside, if you have no fuel pressure how did you expect the engine to run?
Exactly how did you test it? There is a procedure based on how the system works.
The pump has to run in order to have fuel in the injector rails.
Don't look elsewhere and replace parts that have no bearing on this.
With a gauge on the test port, cycle the ignition on and off several times slowly.
If no pressure builds, does the pump run a few seconds each time the key is cycled to Run and off with NO cranking?
If no, reset the crash sensor behind the passenger side kick panel.
If still no check the fuse that feeds the pump.
If still no, consider replacing the fuel pump. It's in the gas tank.
You must use common sense and do testing before replacing parts or coming to conclusions and waiting time and money..
Good luck.

 

I used a fuel pressure gauge. And as I said the gauge won't even register. The fuel pump engages when you turn the key you hear it pressurize. How do you test the crash sensor? If the fuel pump energizes, does that mean the relay and the pcm are working?
The fuel pump runs for 2 seconds each time the key is turned and shuts off when not cranking.

 

If you hear the pump run, that eliminates everything else.
No pressure, change the pump assuming there is enough gas in the tank.
Good luck.

 

Test your fuel pressure gauge and make sure it isn't broken. If the engine runs, you do have some fuel pressure.