V10 Eng, desperate in need of help

time2roll wrote:
At 124,000 I suspect the fuel pump has quit. This can be a bit of an intermittent issue for months until it completely gives up. (don't ask how I know) The shop I had took maybe 20 minutes to go down the check list and confirm the pump.

If the plugs have not been replaced ever this would be a good time to get that done too. Consider replacing the ignition coils too if you do the plugs.

Fuel pumps can be problematic, but I must disagree with this armchair diagnosis.

Fuel pumps CAN well exceed 200,000 miles, my old 2003 F250 5.4 was at 240,000 miles when I sold it with the original fuel pump. Our old 93 Mercury had 140,000 miles when we sold it with original fuel pump, our 97 5.4 had 140,000 miles when we sold it with original pump..

Fuel pump should be diagnosed properly with a fuel pressure gauge on the fuel rail. Low or no pressure when the failure happens and you have now isolated it to the fuel system, then you would have to determine if it electrical system issue which causes the pump to stop running.

If fuel pressure is correct when the issue happens then you would need to look elsewhere..

OPs issue seems to be happening only when making a left or right hand turn, but has happened with full and not full tank.. Could be debris or water in the tank perhaps, don't know but would hate to see the OP go through the hassle of dropping the tank to replace a fuel pump and it does not repair the issue.

It could even be the ECU failing, a wire chaffing issue, bad grounds, broken wires, water damage in fuse panel/BCM (water leaks from the windshield are a consistent problem in this yr, water drips down onto the drivers side onto the top of the fuse panel which is a "smart" panel with BCM corroding connections), TPS (throttle position Sensor), weak battery or charging system, speed sensor, vacuum leaks (the age of this vehicle and mileage OPs vehicle most likely has a few vacuum lines on the verge of snapping off)..

Age is against this vehicle making it difficult to diagnose from behind a keyboard.

This vehicle has a very limited OBD1 ECU and sensors with OBD2 interface giving a very limited look at the system while running. OP may need to come up with a fuel gauge to connect to the fuel rail and somehow be able to read the gauge while driving.

Op would need to also check/monitor the voltage applied to the fuel pump while driving to see if there is an electrical issue causing the fuel pump to cut out.

OP may need to check every connector and every ground connection for corrosion damage or broken wires..

If it is stalling only when making turns and no other times, a very good chance there is a chaffed or broken wire which IS a common issue..

Be aware, there can be many HIDDEN wiring splices inside any of the wiring harnesses which often become problematic over time..

HERE is an example of many that I found just with a simple Internet search, the poster there had a 2003 Expedition which would stall when making left turns. Turns out it was one of the wires chaffing and shorting in the wiring harness connection to the battery.

If I was in the OPs shoes and really wanted to go on their trip without the nagging thought of this thing croaking while traveling I would suggest looking into perhaps renting a truck if fixing for sure or buying a new truck isn't happening.