Summers22

iTrader: (2)

So today I went to pass a tractor on a rural road, put the throttle down and flew right on by (passing gear kicked in), then about 5 seconds later as I coasted back to speed I had a stutter and hesitation for about a mile every time I gave it gas. This slowly went away. About 5 miles later I pulled over, turned off the truck and scanned for codes. No codes, good. Started it up and she ran perfect as usual all the way home (about 10 miles). When I got home, I adjusted my WOF fuel on my Gryphon down from +1.85 to +1. I am thinking too much fuel caused the issue as it cleared up pretty quickly. Anyone have any insight to the issue? I havent looked at my FPDM lately, but it is original and I added stand-off to it. Also the fuel filter and air filter are new in the last 15K miles. One suggestion was a shortage of fuel, but passing gear kicking in and tons of power kind of kill that suggestion, it was only after letting off the gas then coasting that it did this upon acceleration. Thanks for any ideas.

PerryB

Do you know at what throttle % the WO fuel trim override comes in ? I would guess around 85%. Considering the delay between coming off WOT and the stumble upon your relatively light re-application of throttle, I'm inclined to think this is not an overfueling issue. It seems to me like when you came back in with the throttle, there was not sufficient fuel available. I think the pump was slow in ramping back up. FPDM maybe? They're hard to nail down because the symptoms can be all over the road. I also don't think its the filter because that'll show up almost immediately when you put the hammer down. Of course it could also be the pump itself .

PerryB

Also, do you know how the driver module (FPDM) senses fuel pressure? I'm wondering if there is an external sensor or if its integral to the module.

Summers22

iTrader: (2)

Thanks for the thoughts Perry. I tried to simulate the issue on my 22 mile commute this morning. It ran perfect. I will say fuel pump is on my mind, only because I just changed it in my 07 Expedition with the same milage. I will inspect the FPDM this weekend.

elricfate

I bet that FPDM has some serious oxidation and a cracked carrier causing a short in the board.

BadFish523

I be curious to see. Because it is original however he said he added a stand off to it so its not directly up against the frame rail. I am planning on checking mine here soon (no issues just preventative) and if mine is still in good condition I will put in a spacer to help it last longer. Summers if you can get a pic of what the backside looks like when you check it. Im interested to see how much the stand off has helped.

Summers22

iTrader: (2)

Sure, but I sprayed it with black bbq paint when I did the stand-off spacers. Will report back.

4.6owner

Sounds like a fuel pump issue. Other Fords of this era had TSB's regarding a similar issue or long drives at high speed while cruising and getting off the throttle. A data log would tell you if that is the case.

Summers22

iTrader: (2)

Thanks 4.6owner. After 50 more miles of driving, no symptoms. I did drop the spare and remove the FPDM. Zero corrosion thanks to the stands I used. So thats ruled out.

Summers22

iTrader: (2)

Sidenote, this gives me a reason to research 13-14's with the 5.0..........