Diagnostic Trouble Code 556
I have a 1995 F150 with the 4.9L I6, 5 speed, XL pkg, 183xxx miles. I replaced the fuel filter, plugs, and wires due to it bucking at any speed intermittenly, and stalling a lot while idling. I also ran some fuel injector cleaner through it. Anyway, it only bucks now intermittently at highway speeds and will still stall sometimes when idling. I also have to rev it up a bit more to keep from stalling out on takeoff. I bought and used a code reader and it came up with the code 556, (fuel pump primary circuit failure). Anyone know how to fix this problem? Any ideas if it's not this?
Secondly, I've noticed my speedometer goes wacky, and I would like to replace the sensor or cable, but I've looked on the transmission and there is neither. I checked the rear differential and found what appears to be a sensor, but no speedo cable running with it. Is that still possibly the speed sensor? The chilton manual didn't show a picture of where it was located, but only states it's on the tranny.