Random engine shutoff

[BlackCoffee]

I had similar symptoms before the fuel pump went. Opening the door de-energizes the relay next to the fuel pump real. It may be the fuel pump relay going bad or heat related from corrosion in that area. It could be pump or relay. If it you have a fuel pressure gauge, you an it happens again, hook it up to the Schrader valve on the fuel rail. If it is zero, there is a good chance it is the pump. You might also monitor the pump for pressure when it is working. I have seen them read low or too high before failure.

 

[Fordguy32]

If 04 is same as 03 as far as fuse panels I can almost guarantee your problem is in the circuit board attached to the back of the fuse panel behind passenger side kick panel. You will need to remove the whole fuse panel and disassemble (make sure to take pics while you do to remember where fuses and other things go). You will find a circuit board with 4 micro relays in a row soldered to the board. You will probably find one of the micro relays has a melted spot on its side. That’s your problem. New relay is cheap and I took mine to a electronic repair and paid $35 to get it soldered. If your good at soldering you can DIY. One thing to remember though is that some (or all, I can’t remember) of the soldered connections require a connection to the circuitry on both sides of the board. If one is not made it will not work correctly. I have pics somewhere if you want them. Haven’t had a problem since

 

[Holochron]

I had the same prob with my 2003 5.4 eb. It turned out to be loose corroded battery cables. (I think. It may just have not had time to happen again because of what happened next) Later after leaving it to sit for a week it had a no crank, no click issue. I was told by my father-in-law who is a mechanic, and by Scotty Kilmer on his forum that it was likely my ignition switch. I really didn't want to have to mess with that. Long story short I did a continuity test on every fuse they were all good. Then I started pulling all the relays from the fuse box to see if any were corroded or bad. The first one I came to was the PCM Relay R203 which the manual says controls fuse 32,33,and 34, Fuel pump relay , Fuel Pump, PCM solenoids and sensors. It is a less than $5 part at the ford dealership near me. I heard a fuel pump that is going out could cause the relay to overheat so I bought a few extra relays just incase. My theory is that the relay was going bad causing the truck to shut off randomly.