Hi guys, new to the forum, but I've hit a brick wall. I have a 2004 ford f150 V8 4.6l and i cannot for the life of me figure out why it wont stay running. I received it from my cousin who said it had been sitting for years, but ran great. Little did i know the world of issues i was going to run into. So the truck starts up great engine sounds like its mechanically perfect. After about 15/20 seconds it will rough idle and bog out and stall. I thought it was a fueling issue, so i replaced the following, fuel filter, fuel pressure sensor, fuel module, Maf sensor, and pcv valve because those codes were also being shown when i had the scanner hooked up. I also checked the fuel pressor while i had the fuel filter off and it seemed to be pushing out a pretty hefty stream of fuel so i think that's good. Now after each part i replaced I would disconnect the battery for an hour or two to reset the codes and then would reapply power and start the truck up. It ran great all day no check engine light every time all day, no rough idle, no bogging/ stalling out. The next day the check engine light would come back on and i would have the same issues. Each part was put on a few days apart. It would Starts up perfectly and then rough idles for 15 seconds and stall. No ticking, no long cranks. It will fire up on the first key turn. Just wont stay running. I called a mechanic shop local to me and read them the 2 codes being P0191 (fuel pressure sensor circuit/range) and P0402 ( EGR 'A' flow excessive). After telling him all that i've done already he said that it sounds like it is some sort of powertrain programming or sensor issue. Those were the other two solutions he had saw on his computer after crossing off the repair i had already done. He said that i should take it to a ford dealership for further diagnostics since i replaced all that they would have already. Any insight or tips would be a huge help. Really stumped at the moment.

 

I'd do some of the pinpoint tests in the PCED for the two codes
Most likely you need a new fuel pump (for the code P0191)
Most likely you need a new DPFE sensor too (for the code P0402)
I'd do some of the pinpoint testing to be sure before just throwing parts at it

 

You need to measure the fuel pressure. With the engine running fuel pressure should stay at around 40 psi.
Look at the video below and jumper the connector for the FPDM and see if it resolves the issue and confirm its a FPDM issue. Many, many of the aftermarket FPDMs are junk.


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if it had been sitting for years like you say, could be bad gas... drain the tank and replace the pump, clean injectors and Throttle Body. look for rodent problems.

 

so even if the fuel pump is indeed still working it could be going bad causing the startup and almost immediate bog??? I did turn the key into accessory mode when i changed the fuel filter and fuel pump seemed to be pumping out a pretty consistent amount of fuel. Wouldnt it not turn over at all if it was a fueling issue with the pump?

 

I dont think its bad gas the truck was running fine for about 3 weeks. Put probably 10, 1/2 tanks of gas in it before this started happening.

 

Ill get a new dpfe sensor, but would a sensor really make the truck bog out after only 10 seconds of idling?? When i replaced the fuel filter i turned the key into accessory mode to see if the fuel pump was pumping out a good stream, and it seemed to be a pretty hefty stream of fuel going into the drain pan i had set up, poured out a gallon of gas in about 15 seconds. A failing fuel pump would cause this? Wouldn't the car not even start if the fuel pump was going bad?? Not enough fuel air mix???

 

The truck can run with a failing fuel pump, it will just run poorly
Keep going on the pinpoint tests for the codes you have
+1 for post 4
I'd replace your in tank fuel pump

 

Next time it idles for 15 seconds and starts to die, cycle the key on and off and on and off
See if it then picks up and runs some more
If it does, the fuel pressure is low, and the re initialize with the key gives the fuel rail another squirt of fuel from the pump
If you disconnect the fuel rail sensor, the fuel pump goes to 100 percent duty cycle for testing
Try that too
You need a new fuel pump IMO
Your 04 should NOT have a fuel pump driver module, but check back by the spare tire anyway

 

he stated he already replaced the FPDM... did you check the ground wire that attaches to the frame ?