Hello,

I picked up a 99’ Ranger prerunner with a 3.0 FFV about a month ago that has been giving me some engine issues that I cannot figure out.

Problem:
From a cold start, the engine loses power after 20-25 minutes of driving or idling. It will start right back up after two cranks but loses power intermittently with decreasing time between each event.

I took a video watching the fuel pressure taken from the fuel rail it and does not go below 45 PSi when the engine loses power. Immediately after losing power, the fuel pressure reads the KOEO pressure.

Return Style Set Up
- 22 Gallon Fuel Cell w/ foam
- 1/2” pick up hose to 40 micron fuel filter to pump inlet
- 3/8” from pump outlet to FPR
- 3/8” from FPR to fuel rail
- 3/8” return from FPR to fuel cell

Diagnostics:
Fuel Pressure
-KOEO: 57PSi
-KOER: 48 PSi

Codes: Appear to be because of missing sensors
- P0232
- P0460

Parts Replaced:
- Cam Position Sensor and Synchronizer
- Replaced Vacuum tube to regulator from intake
- 190 LPH in-line pump
- Rerouted return line inside fuel cell
- Replaced fuel filter

Items to Check:
- Vacuum line of FPR on rail
- EGR system
- Injectors
- Spark plugs

 

What about exhaust blockage?
Is it straight pipes or are the Cats still there

Also 1999 ran a Returnless fuel system, 1998 and up Rangers, ran 55psi pressure

So not sure what you are referring to
1997 and older had an FPR(fuel pressure regulator) on the engine attached to vacuum line and Return line, but ran 30-35psi pressure

1999 had FPR in the tank on the fuel pump assembly, no vacuum line, some years used a 3 port fuel filter that had a return line back to the FPR in the tank assembly


Other thing that comes to mind is an air lock in the gas tank, fuel cell, as the fuel is pumped out a sealed tank can get air locked, high negative air pressure inside the tank
I assume you are not running an EVAP system, if you are it may be causing the problem
Try loosening the gas cap, so venting the tank, and driving to see if problem reoccurs, just a test