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A. Hennessy

A. ... 1/9/2021

2009 Ford F-250 Super Duty XL 8 Cyl 5.40L


P0191 code changing sensor didn't fix now what

started no notice it was losing power when accelerating to merge onto highway. Notice this next time I drove it and check engine light came on. Code reader says it has a P0191 code fuel rail pressure sensor. Tried replacing the sensor but it changed nothing. What should I do next? The truck starts every time no issues there. You only notice the issue when trying to pick up speed to merge onto highway for example and/or when climbing a hill. It really lags when climbing a hill. Any thoughts?

1 Answer

Teddy B

Teddy B 1/10/2021

Take a look at the Fuel Pump Drive Module under the truck at the rear.

Watch some You Tube Video on that.

While the Regulator is apparently a common failure on yours
I haven't found that to be true hardly ever on most vehicles.

Even if you resolve the issue,don't ride around with old spark plugs,
old O2 Sensors.

I find most all 5.4 have ignition coil failure,then the O2 & so goes the exhaust
converter from misfires.

You need to look a Scan Tool Data & be on top of all system items a couple times a year

Some vehicles you can drive for years & do nothing & others you can't & have one that you
need to understand & be on top off.


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