alright i have a 88 f150 with a 87 5.8 351 and a 89 5 speed tranny
now about a month back i was driving one day and as i hit a hill it started to fall on it self and wouldnt make it up, like it wasnt getting any gas so i replaced the fuel filter and it got worse for whatever reason it started doing it everywhere flat ground even while idling, feels like its just not getting any gas to it so i got it hooked up to a fuel pressure and volume tester and it was reading only 30lbs of pressure so i replaced the fuel pump but still nothing any ideas?
Heres a list of things i have already replaced:
Fuel Filter
Spark Plugs
Spark Plug Wires
Fuel pressure regulator
Fuel Pump relay
Fuel pump

 

Checked voltage at fuel pump? Could be ground causing high resistance/low voltage to pump. Check and clean all grounds. C
Not to jump on the "Bad PCM" thought, but may want to check the circuit board for burnt traces and leaking/bulging capacitors.

Also, have you pulled codes? Check using either paper clip/ analog multimeter or appropriate scan tool able to read OBD1 codes. Have seen stuck open EGR valve similar problems you are describing since manifold vacuum was low giving an indication of weak fuel pump. Just a couple of thoughts....

 

thanks man i appropriate havent got any codes on it yet when i saw low pressure in the pump jumped the gun thinking that was it for sure but doesn't seem to be. and i forgot to mention but i have mine running off one big tank the second tank is disconnected. when i replaced my plugs they were pretty burnt up. im just really hoping its not my computer seeing a few other posts on other websites somewhat close to my problem and it was there computer. but am also seeing map sensors and egr valve and tpi sensor think it might be any of them?

 

You'll need to run the Key On/Engine Running test to check for any codes that would result in limp mode operation. I would run the Key On/Engine Off test to see if there are any stored codes first. It would be better than throwing parts and money at it. You have done plugs and such, it's time to get into the nitty gritty.