Howdy folks.. I'm a newbie to the site, but not a newbie to my ford trucks.
I've got an 05 FX4 5.4 3v.. It's been giving me fuel issues. Lean condition, low fuel pressure on hard acceleration. Bucking/surging throttle, particularly when outside temps get above 27*c or so. Cuts out and snaps when trying to accelerate hard. Recently when it's hot outside and the engine warms up it will start idling rough and die. Once the engine cools it will fire back up like nothing happened. I had the fuel pump driver module rot out a couple years ago, lost my fuel pump then. But figured that out and changed it myself. It's been doing the leaning out thing previous to that problem though.
Fuel filter has been changed routinely. Just did it again not long ago. I know it's electrical but I don't really know where to start.. Vaccuum signal to the frps is good, no leaking fuel.

Fuel pedal? Wiring harness? Grounding issue?

I live in northern Ontario and the truck has about 250,000k on it.

Warm weather is here and I can't afford to let the dealer mess around with it.
Anyone please have any insight from previous experiences?

-Jon

 

Have you checked the FPDM again?

 

How would I test it?
I found a post made earlier showing which wires were constant power and ground, as well as the duty cycled ground leads but I've lost it. It has been leaning out under load for a long time too though. Last time I was tracing wires I found that the grounds have been cut and spliced to bypass the connectors leading back under the cab, so leads me to believe there was issues with this truck before I bought it. I've had it 3-4 years now..

Makes me really miss my old 81 frankentruck.

 

Just food for thought..I have an 05 F-150, same engine...My truck was throwing lean codes. Long story short, the fuel injectors on the 05's are crap. There is a service bulletin on the injectors.

 

Thanks for the heads up. Could be why it was still lean under load after I swapped the fpdm.. But I there's something else causing me to lose all fuel pressure when it gets close to 30*c ambient and the engine gets warm.

 

The 05 fuel injectors don't cause a lean condition, they leak and go rich.