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Michael, Ford Senior Master Technician
Category: Ford
Satisfied Customers: 275
Experience:  Ford Senior Master Tech & ASE Master w/14 yrs exp. Served on Ford's Tech Review Panel
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2005 ford f150: pressure sensor..the check engine light comes on

Resolved Question:

i have a 2005 ford f150 4.6l automatic. the fuel rail pressure sensor keeps going and the check engine light comes on. it seems to do it when i get the truck down shifts into higher rpms. what should i be looking at next. the dealers cant seem to figure it out. thanks
Submitted: 8 years ago.
Category: Ford
Expert:  Michael replied 8 years ago.

When you say the fuel rail pressure sensor keeps going, what exactly do you mean. Has the dealer replaced any parts for this issue? What code is the computer setting for the check engine light?


Thank you,


Customer: replied 8 years ago.
the code is p0191. the dealer replaced the sensor three times now and the check engine light just came back on
Expert:  Michael replied 8 years ago.

Jason_morgan1, the dealer is chasing the wrong problem. The P0191 code just means that the fuel rail pressure sensor has detected that the fuel pressure is going out of range. The pressure could be either too high or too low. P0191 almost never indicates a bad fuel rail pressure sensor.


You are having a fuel pressure problem. Since you say it normally happens at higher RPM's you may have a clogged fuel filter. Chances are though you need a fuel pump. While this is not a common problem, I have seen it several times before.


Hope this helps, if you have any further questions do not hesitate to ask.





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Customer: replied 8 years ago.
the truck is a 2005 with 23000 miles on it. do you think the filter would be clogged?? every now and a gain the it takes a couple of times to start the truck. dont know if this helps to narrow it down??
Expert:  Michael replied 8 years ago.

Jason_Morgan1, I doubt you have a clogged fuel filter, but there is no way to tell without removing it and checking. A fuel pump going bad, or a fuel injector leaking down can cause a hard to start problem. A fuel injector will not cause a P0191 though.


I am 95% certain you need a fuel pump. Using a scan tool to watch the FRP data, you would most likely see the fuel pressure drop on hard acceleration and higher RPM's.


If I can be of any further assitance just let me know.