Shut off while driving, then code P0191 appeared

ADAM C MABIE

MEMBER
2007 FORD F-150
5.4L
V8
4WD
153,000 MILES

My truck stalled out while driving and tripped a p0191 code. Now it will start initially, and the fuel rail pressure is normal but after a few minutes at idle or after raising the RPMs the fuel rail pressure drops and the trucks stall out. Both banks are adding between 20 and 50% fuel before it shuts off. Does this sound like a bad fuel pump? I changed out the fuel pressure regulator with no change. The fuel filter was replaced 10,000 miles ago.

Sunday, July 10th, 2022 AT 5:53 AM

3 Replies

KEN L

MASTER CERTIFIED MECHANIC
50,087 POSTS

This is common when the fuel pressure rail sensor goes out. here is a video of the replacement on a similar car with instructions in the diagrams below to show you how on your car:

https://youtu.be/A9dbXbydGro

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

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Sunday, July 10th, 2022 AT 4:24 PM

ADAM C MABIE

MEMBER
2 POSTS

I’ve done this. Still no change. I also replaced the fuel pump and the issue is still there.

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Sunday, July 10th, 2022 AT 5:59 PM

KEN L

MASTER CERTIFIED MECHANIC
50,087 POSTS

Can I ask if you changed the fuel pump driver module? I have seen these go bad and act like a bad fuel pump, did you use a Motorcraft pump? Here is the location of the pump module so you can check it out. Remove the electrical connector and look for water damage which is common. Check out the diagrams (below). Please let us know what happens.

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