bobothehobo

Yes i do have multi meter and can use it. Schematics would be great

ProjectSHO89

Instructions:

1. Disconnect battery negative terminal before making any resistance checks.
2. Do NOT force your probe into the female connectors, that usually damages them Backprobe only.
3. Verify the continuity of the pressure sensor line between the sensor and the PCM connector. PCM disconnected.
4. Same for the signal return line. PCM disconnected.
5. Reconnect PCM. Check for continuity between signal return line and battery negative cable terminal. IIRC, signal return and chassis ground are connected together either in or at the PCM.

bobothehobo

Found bad ground, repaired and problem solved. CEL and ABS lights out now with no codes

Neil Kominek

I am having similar issues, where was the bad ground?
With mine, it runs fine if the FRPS is unplugged. When I plug it in, it will run for a little bit with the FPDC going between 15% and 40%. The FPDC will then jump to 75% and stay there, the truck will start running like crap and will sputter when the throttle is pressed. Eventually, the plugs will load up and it will stall.
I changed the FPDM and FRPS (FRPS was from a junkyard)
With the FRPS disconnected the FPDC ranges from 15% to 35%.
2007 XLT 5.4 3v

bobothehobo

Mine was under the passenger floor, close to the starter

Neil Kominek

Heh, I just had to change the starter today too.

bobothehobo

thats exactly when my problem started. After I changed starter

Neil Kominek

Mine actually started almost a week after doing coils and plugs. The truck ran perfectly for 4 days and then one day, after a big rainstorm the night before, I pulled out of my garage (the truck was backed in with the nose sticking out), when I put it in drive it started sputtering and would barely move. I could smell gas from the exhaust. I pulled it into my yard and pulled the codes of the OBD and got p0191 and the codes for rich at the O2 sensors.
The next day I had the epiphany to try to run it with the FRPS unplugged and it started and ran, rough at first because the plugs were a bit fouled from the rich condition that was being created.
I have changed the FRPS with one from a JY, the FPDM was from a JY but is obviously new, the fuel filter, and now the starter because it went out.

bobothehobo

My was running rich too until I replaced FRPS too. About $20 plus shipping for motorcraft from Rock Auto.com

Neil Kominek

I plan on getting new but I could not spend $110 on one local and could not wait for shipping as I am supposed to be leaving on vacation in the AM, pulling my camper with said truck, 250 miles.