Yo guys,

5.4L 2005 f-350. I was driving up a hill today and all of a sudden the truck started misfiring very violently. I pulled off the road and turned it off as it didn't even have enough power to get up this slight incline. As soon as I pulled off the road I threw the scanner on it and it was throwing a p0191 and p2195. I leave engine off for five minutes and start truck up, no misfires and its running great as of right now.

Just for context:
P0191 - Fuel rail pressure sensor A circuit range performance
p2195 - 02 sensor signal biased stuck lean bank 1 sensor 1

The check engine is not on for some reason but when I plug scanner in it gives me these codes. I would like to throw a pressure tester on the rails and check it's optimal but I am not sure where to place it as there doesn't seem to be anywhere to test. There's just the flow line into the rail and the FRP sensor. Aren't there little schrader valves or plugs to test on the rails. Any advice appreciated on where to go here as I've never had to mess around with the fuel system on these.

P.S The truck doesn't throw any codes, but also everytime I turn the truck on it idles very high until I put it into gear which I assume is an EVAP cause. I've been having EVAP issues and have replaced both the purge and vent solenoids and still have back pressure not allowing me to put gas in truck without pulling the purge valve off everytime I go to get gas. Just in case the EVAP system could be causing something with the rail pressure, I have no idea here

 

I don't know for sure, but I think the test port valve was deleted in 2004.
Our 2003 5.4 2v has such a test port and it is nice to be able to test the fuel rail pressure with a gauge.
I think there is an aftermarket adapter available that can be placed under your fuel pressure sensor to provide a test port.
The adapter provides a port for a pressure gauge so you could just screw in a small pressure gauge, I have one like it on our boat.

 

For the engines with only the FRP and no Shrader valve, you have to install an inline adapter, either at the FRP or at one of the other fuel line connectors in order to use a mechanical gauge.

 

So the irony here is the FRP sensor may be wonky....but the way to check otherwise is the live data FRP value on your scanner.

I guess if you must check the sensor against real-world, you'd definitely need an adapter

 

Only have a code reader nothing with live data sadly. So if it's throwing an FRP code is there anything that could be possibly causing it to throw that code that isn't the sensor itself or should I just spend the money on a new FRP sensor? Thanks

 

Since you have a code for a lean condition, I doubt changing the fuel pressure sensor will resolve your issue. The only way to make the correct decision is to read the fuel pressure, then make your diag decision.

-- Dave

 

Have you checked the vacuum hoses for any leaks or soft spots, particularly the PCV hose into the throttle body?
Or loose exhaust connections between the engine and the O2 sensor?

 

Diagnose the P0191 DTC first.