Fuel problem?

[Mnicholson32]

I've got a 01 expedition with the 5.4L I believe I am having a fuel pump issue, vehicle will start just fine runs well idles fine, however when I start driving it frequently wants to lose power and try to die when first accelerating, when I push harder on the accelator the vehicle comes back and drives just fine. I do know that the actual fuel gauge is inaccurate. The digital gauge up in the middle console will say 100 miles to empty. Any thoughts? Thanks in advance.

 

[Rich_007]

I got the same year/motor. Try to rule out the cheap/easy first. Wanting to die when you start accelerating but then responding almost sounds like a large breach in the integrity of the intake/vacuum. Like the motor thinks one thing based on maf input, but reality downstream is different. I would think anything causing that much hesitation would be throwing codes at you and you didn't mention any. Maybe clean the maf sensor. Verify the air filter isn't clogged up.
When my fuel pump when out, it just died, it didn't behave erratic based on demand, but I guess they could. Maybe check the fuel pressure at the rail. There is a schrader valve on the rail, will take you about two seconds. I think the numbers might fluctuate under load, so maybe have someone rev it up so you can check it under load and at idle. That would rule out fuel issue if you are pretty sure that's the prob. Fuel filter is kind of of easy to change. I don't remember the values. 35 at idle comes to mind, but verify that. I am sure there is a psi range listed on here somewhere that tells you what it should be.
Good Luck
Let us know what you find.

 

[VoxVeritatis]

When I began having fuel issues with my 2002 around 160K miles - unrelated to filter - it was the original factory fuel pump. It wasn't difficult to diagnose. It would start, but began to stutter under load, and eventually wouldn't even start. Bought a lifetime-warranted plug-and-play aftermarket from O'Reilly, dropped the tank, removed the old unit (sender and pump), installed the new one. It's worked perfectly ever since. And that includes the less-than-25(?) miles-to empty warning light.

Agree that pressure is easy to check using the Schrader valve on the rail of the 2V 5.4L. You don't need anyone to rev it for you. With the plastic 5.4L cover off you can access the throttle assembly and work the throttle by hand while you watch the meter. O'Reilly loaned me one for free (pay deposit, return the unit, and they refund the deposit). Many (most?) parts shops do the same.

 

[knewblewkorvett]

I pondering the same question with my 97. If I put more than 300 miles on a full tank of gas and throttle hard, it will sputter. It never sputters before the 300ish mile mark. When I fill up I'm only putting in like 20 gallons so that leaves 10 gallons in the tank yet it acts like she is almost out of gas. Fuel pump problem?

 

[FoothillsJim]

Just replaced the fuel pump on my 1999 Expedition XLT 5.4L 4x4, 135,000 miles. The symptom was engine turning over but not firing/starting - only sometimes, but got worse quickly. Sometimes you would hear the pump run when key turned on, and sometimes not. Ran fine once started.

Replaced the pump and all seems fine. One problem I had was at the 20 year old electrical connector from the fuel pump assembly that connects to the harness at the inside of the frame next to the tank. The locking tabs broke (perhaps brittle, but probably my fault, I could not really tell what I was doing when trying to release the connection). I tried electrical tape to keep the connectors together but they did slip apart enough for an intermittent connection that I has to diagnose when it stopped running 60 miles from home.
Just a heads up to take care on releasing this connection.
I now need to figure out how to better secure it together without the locking tabs.

 

[rjdelp7]

Hold your trip reset while turning on the ignition. It will put odometer into test mode. Press trip reset to scroll to FP(fuel pressure) and DTC(dianostic trouble codes).