So I think I have a fuel pump problem. But it's strange. Don't know where to start.

I bought a half a tank of fuel the other day and everything was normal and fine. Truck drove a mile and sat in the driveway for 6 hours. I jumped in the truck and tried to start it and it took an extra couple revolutions to start. (Weird)
And then I didn't even drive 100 feet and the truck started to spit and sputter and lose power when applying more gas. The lighter I was on the pedal, the better it ran. My first thought was "I bought bad gas"... Sediment, water,,, something! But it continued to run like crap. However, it idled perfectly. The more gas I gave the truck, the worse the stalling and bucking got.
I drove it for several miles, and it was unchanged. On the way home, the problem eliminated itself. Gone completely! I got home. Put a can of seafoam in the tank and let it sit over night. Got up for work the next day and the problem has returned. (I hoped it would stop on it's own again)
Got on the HWY and made it to about 60mph and it was bucking and spitting and losing power so bad, I had to pull it over. An that's when it died. Took 10 minutes of grinding to get it to start again. At that point I knew it wasn't safe to be attempting to drive it home and kill someone, so my baby saw it's first tow truck in 160,000 miles!

Now that it's in the garage, I can hear the fuel pump spitting and sputtering, almost sounds like it's sucking air. While I was revving it and messing with it, it threw a check engine light. There were three codes on the scan tool. Low fuel pressure at the fuel rail and two different lean mixture codes. (Can't remember the code numbers, can run them again tomorrow)
I am RELIGIOUS about maintenance and care on my truck. So it's had all the replacements it's supposed to.
Fuel filter x3. Last replaced about 3 months ago.
Coils, plugs x3, and wires.
I frequently clean the injectors
Gets a little seafoam about every two months down the booster and in the tank.

I pulled the line off at the filter and turned the key on to let the pump run and it comes out of the line with decent pressure but it is spitting and sputtering out if the line as well. And it doesn't seem like it's got 70psi of pressure on that line. Not sure how much pressure should be at the filter. But it's not 70psi.
The audible spitting noise that the pump is making has NEVER been heard before by me. And I start my truck every day in a garage. I would have heard that. I notice every little noise my truck makes.
I know that the modules under the spare corrode and a lot of guys have had them short out. But wouldn't that just kill the power to the pump all together?
I guess I just don't want to bight the bullet and buy a new pump.
What do you all think? Suggestions and ideas are always appreciated.
Thank all of you for your responses ahead of time.
Oh..... It's a 2004 f150 supercrew xlt with 4.6 liter. I'm sure I should have already said that.

 

Drop the spare tire and take a look at the Fuel pump module, if it's corroded then that is probably your problem.

Also do a fuel pressure test and post the numbers and I'm sure someone here could help you out.

 

There is no test port for fuel pressure - you need a scan tool to read the PID on the OBD2 port.

FPDM:

 

The FPDMs can slowly start screwing up, so it isn't always a "it was working and now it's not" kind of thing. But I haven't had trouble with mine and don't know exactly what goes on with them.

 

Well I just bit the bullet and ordered a Motorcraft pump and a module. I'm hoping that it's just the module and not the pump.
The only thing I'm worried about is that it seems like a demand problem. The more gas I gave it, the worse it got. If I let of the brake and barely touch the gas and get going slowly... It would hardly buck and skip. But if you mash the gas it would almost kill the truck. Electrical problems are a real nightmare. And I know they can boggle a lot of people. Maybe I'm over thinking it.... But I'm worried about the spitting noise I'm hearing from the pump.

Still think it could be the module?

 

Hi.

And yes - the FPDM regulates fuel pressure based upon demand ( e.g load).

Good job getting the Motorcraft unit. I can no longer recommend Dorman products. Their FPDM's appear to be dropping like flies unexpectedly. So, despite their 'lifetime' warranty - which does you little good if the thing dies on you in the middle of nowhere - I'd steer well clear. Don't care if they are cheaper - not with their failure rate.

(Side note - carrying an onboard spare is a good idea).

(Side note #2: Dorman cam phasers are a must-avoid item as well. Vanes are breaking randomly and catastrophically. Making the use of these false economy, considering the significant amount of work it is to replace them. Stick to MC.)


Dorman phaser failure @ ~3k miles:




good luck
MGD

 

Thank you all for your quick responses. You guys have great advice and I've leaned a ton from you all.

I think I'll keep the Dorman part as a backup and put a motorcraft module on the truck. I've read that there's a new mount for the module to help the corrosion issue.
I'm headed to the garage to get dirty.... I'll post again with whatever I find.

Thank you all for your help. Cheers!

 

Thanks everyone for all your great advice!!!!!

My truck is fixed!
It was the fuel pump module. I really wish I could post pictures from my iphone onto this site... Out of all the pics I've seen online of corroded modules. Mine was the worst! There was no alluminum backing on it anymore. The circuitboard was completely loose and moving freely inside the housing. That thing was shot! The new module completely fixed all the problems.
Thank you guys so much! All your advice saved me hundreds of dollars and a couple of lost days at work!

For anyone reading this thread... If your having fuel problems with your 04-08 F150, check this module!!!! Mine was causing the pump to make noises and sound like it was sucking air and pausing fuel flow. It caused the truck to buck and sputter and die. Sometimes the truck would idle. Sometimes it would idle rough, and then smooth. One night it ran fine, and an hour later it ran like crap. The truck wouldn't even get over 50mph without violently bucking and jerking. This module really does mimic fuel pump problems. And some of the rough idle seemed to mimic a bad coil.
All of the advice I received on this thread was spot on! Even the check engine light reset itself after replacing this module.

Thank you all again for the help and awesome advice.