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Engine Stalling upon Stopping after New Fuel Pump

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New User

Aug 19, 2019, 8:34 AM

Post #1 of 7 (350 views)
Engine Stalling upon Stopping after New Fuel Pump Sign In

Hopefully you guys can help me, because my mechanic and I are stumped.

Car Specs:
-Ford Expedition, Eddie Bauer, 4WD, 5.4L 8Cyl.
-Over 175k mileage

My car's fuel pump went out last month and I purchased a new pump from Autozone and had my mechanic install the new pump and a new fuel filter along with it. The pump is correct for my vehicle, but it is an electric pump.

Prior to the fuel pump going out, the car could stop and continue with no issue.

What's Happening Now:
I can bring my car nearly to a complete stop, but if the RPMs are still up and it is continuing to roll, it will not die. However, if my car comes to a complete stop; it will stall and die.
The car will idle after start up without dying or rough idle.
The car will start right back up after it dies at a stop sign or stop light.
The car is running smoother than it ever has with the new fuel pump and filter.

Can anyone hazard a guess at where I need to start looking for the problematic system or item?

Hoping you can help. Thanks for reading.

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 19, 2019, 9:04 AM

Post #2 of 7 (338 views)
Re: Engine Stalling upon Stopping after New Fuel Pump Sign In

Did it die with old fuel pump? Was battery disconnected to do this? If so it's not remembering how to idle again would if you can go thru cycles of cold to warm and assorted driving if that. Clue is any pre-sets for radio or other things were lost.
Code reading would show "not ready" your mechanic is stumped makes it difficult now as it's been hopefully professionally check for why first hand not here not in person.
Pressure may not be up to par or not holding well all should be tested.
Who diagnosed that it needed a fuel pump to begin with and why?

All questions, sorry but if mechanic in biz with it right there IDK what I could do that shouldn't have already been check out,


New User

Aug 19, 2019, 9:18 AM

Post #3 of 7 (335 views)
Re: Engine Stalling upon Stopping after New Fuel Pump Sign In

It never died with the old fuel pump. It just went out and it wouldn't start anymore.

I don't believe that the battery was disconnected as the radio presets were still there. Then again, the vehicle was up on a stand, and I couldn't see the battery cables. So, this one, is an unknown.

I've contacted the mechanic several times after the issue began (day 1) and he thinks that I need a full tune up, a new battery, or a full re-wiring (all very costly, and I don't want to do something that isn't going to fix this and just end up costing me more.) There's just a lot of if's happening and I don't have the money for if's unfortunately.

I will definitely have the fuel pressure tested. That may be the entire issue.

I self-diagnosed the fuel pump. It started exhibiting symptoms of a dying fuel pump (chugging on inclines, or acceleration. Bumping and chugging whenever the accelerator was pushed; when car finally wouldn't start, fuel pump was not running with the key in the on position).

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 19, 2019, 9:58 AM

Post #4 of 7 (325 views)
Re: Engine Stalling upon Stopping after New Fuel Pump Sign In

Fuel pumps buzz and shut off when pressure is up with just key on not stay running.
That was the time to pressure check it now no telling if that was the problem. Code readings would help now can get those can help direct where fault(s) are noted.

Nobody wants a part toss guessing game is costly and adds confusion when item by item doesn't work you begin to not trust the new item.
Battery power 'delivered' always matters do check that. Fuse and wire connections to an at fuel pump as well.
Are grounds in place still - stuff like that a good look clean or while looking grease those it's old enough those lose it.
Charge battery if all you can do today. If with a voltmeter alone check with a helper after charged what voltage is. Now go to start when starter engages see how far voltage drops if only at the battery is a clue how powerful (AMPS) that battery can hold a load while cranking not fall below - say 10V would be nice. Never lower than 9 IMO.
It's just a quick easy test it has some power not a complete check out.
Fuel relays can pass thru weak current as engine RPMS rise more voltage plows thru.

Just taking stabs at the maybe list you can do without wild and costly tools may be in the cards to pin this down.
Other: You brought the part to the tech so YOU own it not the tech or place would be protocol. Not all will agree to that. Still if someone did it I don't understand not taking a test drive unless that was done, was fine and now this?
Understood if several things have happened the nickle/dime hits do add up try hard to diagnose out what problems are not just parts. When if on this vehicle several have happened all close together my own checks would be why or what could cause more than one thing or depending just the luck of it.
Plain tune-up items? Your call as routine or codes would tell of faults I would hope,


New User

Aug 19, 2019, 10:32 AM

Post #5 of 7 (320 views)
Re: Engine Stalling upon Stopping after New Fuel Pump Sign In

Thank you very much for your help. This really does give me a road map now. I very much appreciate it.

Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 19, 2019, 10:44 AM

Post #6 of 7 (318 views)
Re: Engine Stalling upon Stopping after New Fuel Pump Sign In

First eliminate all vacuum or air leaks in the system (very important)

. You may have a bad IAC ( idle air control) but try cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.


We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 19, 2019, 11:26 AM

Post #7 of 7 (312 views)
Re: Engine Stalling upon Stopping after New Fuel Pump Sign In

Yes - Vacuum leaks. Should have been corrected by now. From newer whacko elbows I vaguely recall were just junk, splits and wouldn't hold a plastic other hose. Large supply line 90 degree turns.
They might stay fine - any vacuum stuff till touched so much as pulling a dipstick for trans check.

Ha - if so where to find good, better or OE new (why they suked) I used PCV/Fuel hose make a loop you get your right angle lasts for decades then which is what this did!

Good luck sport I/we want you to succeed with the least waste possible,


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