1987 F150 Truck hesitates when giving it gas

ford
f150

#1

The truck will not get up and go. When you step on the gas it cuts out and acts like it is going to die. When you give it a lot of gas in idle it also makes a popping sound. When I first tried to figure out what was wrong the catalytic converter got red hot, so I took it to a muffler shop. They said it was not the cc. They then put a new distributer cap on it and an EGR sensor. Still does not run right. The following is what I have put new on it since:

Spark plugs and wires

EGR Valve

Throttle position sensor

Fuel filter

Fuel Pressure Regulator

Took it to another muffler shop again they said it was not the cc and did a throttle body cleanout. I have put fuel injecter clener in the gas. When there was a gauge on the fuel pressure regulator, the fuel pressure did not go above 30 PSI and when you stepped on the gas, the gauge read between 10 and 5. Also it does this more so when driving rather than idle and especially when you have to give it gas (like going up a hill) and it seems to hesitate more so after being warmed up. The fuel pump is working according the the ASE master mechanic that tested it with his gauges. I am very frustrated and seem to be getting screwed by the shops I take it into because I am a female. HELP ME PLEASE!

1987 F 150 1/2 ton V8 302 5.0 2wheel drive


#2

The fuel pressure(10 psi) is too low and your mechanics are not very knowledgeable.


#3

Yes after countless “This part is it” I have figured that out. Very frustrating. So I am left to figure it out for myself. The two shops I took it to seemed to want to do all these other things that I do not think it needs. They seemed to be guessing and after the first things did not work, I am a bit leary. Needless to say I need my truck! So what would be causing the fuel pressure to be so low? He said I was getting enough fuel pressure from the pump. Thanks


#4

That fuel pressure should be about 40PSI w/o vacuum applied to the regulator. Beware that if (likely you do) you have dual fuel tanks that there are 3 fuel pumps. A low pressure lift pump in both tanks anda high presure one on the frame rail under the driver left foot. The fuel supply/return switchover valve is near the high pressure pump and has a reservoir bowl on it that says “NOT A FILTER.” However, from the factiory in that year they did unitntentionally put a filter in it. You can check for it and if its there, take it out and throw it away. You’ll a new O-ring for the bowl. The low pressure in-tank pumps often fail giving the symptoms you talk about. If one of them is working well, then when you switch to that tank, the problem will disappear immediately. Anyhow, the end pressure is too low.


#5

Thanks you I will check it out.