Hi I have been trying to figure out the p0191fuel rail pressure sensor code on my 2005 f-250 5.4l. I have changed the sensor and fuel filter. Today I got a scan tool that reads the pressure and at a idle the pressure is about 39psi. I took it for a drive with my snowplow attached and the pressure would drop to about 30 psi then I went up a hill and it dropped to 18psi and went as low as 3psi. The truck only does this sometimes. Can anybody help me out with this problem I would really appreciate it. I'm hoping it's not the fuel pump

 

Forgot to mention its a 2005 f-250 5.4

 

Because you're seeing the fuel pressure dropping its highly likely the fuel pump is indeed going away.

Tough to hear but sometimes bad news is the only news.

 

Thank you for the reply JWA. I was not wanting to hear that tho. I was always told that when a fuel pump goes it goes I guess that isn't true. When I changed the fuel filter it was pretty dirty and clogged is there a chance it could be the screen on the pump plugged? Although if I'm gonna take it out to check I suppose I might as well change the pump. Was just hoping not to have to spend another $300.

 

Your issues could very well be the in-tank filter or sock being clogged. I completely understand not wanting to spend more money but honestly once the tank is down and sitting on the ground its a good time to refresh the pump, maybe have the tank cleaned professionally too.

I offer this only because the restricted flow might have weakened or over stressed the pump just enough to have it fail sometime soon. I hate doing the same job a second time if just a few dollars could have prevented it.

Then again if your climate is fair enough (-8 here today. ) or time isn't a concern the simple cleaning of the pump intake and tank might be enough too.