I have an 03 Ford Lightning. The truck rides fine for a while, but after a while of driving, the fuel pressure will drop to almost zero. Sometimes it'll stall, and sometimes it'll try to boost the pressure back up. It seems like its only when I'm hitting the throttle. I can get it to stall without hitting the throttle but it has to idle for a long time. It throws the code p1232, which is something about a fuel pump circuit malfunction. When it completely stalls, the battery light, and the CEL light turn on. I've tried a new resistor, new hi/lo relay, and also bypassing the resistor altogether. new resistor did nothing, new relays did nothing, but bypassing the resistor altogether got rid of the problem. Does anybody have a longterm solution to this problem?

 

What resistor are you referring to ? There is a resistor in the fuel tank, but that is for the float for the fuel level.

Have you checked the normal things :
Fuel filter
Fuel pump & pickup to make sure nothing is getting sucked to the bottom the intake on the fuel pump ?

The DTC P1232 can be from excessive current draw ( with other causes as well ), which in turn the PCM will shut it down.
If the intake plugged by floating debris, this can cause the fule pump to have a heavy current draw.

If the pressure is taken off the fuel system, the debris would be released from the fuel pump until it is drawn up again. ??

 

I'm not sure if this is for only Lightnings or not, but Lightnings have a white ceramic resistor in the front of the truck, behind the bumper that is used to reduce the voltage sent to the fuel pumps.

I have changed the fuel filter, but have yet to look inside the tank.

What else could cause a heavy current draw?

 

Must be, the only white ceramic resistor behind the bumper on the NA version F150 is the DRL resistor behind the Driver's side.