1997 F250 HD 5.8l OBD1

I've been dealing with an issue for about two weeks and I'm not sure where to go with it.

I've been having an issue where my truck will fall on its face on the highway or going up hills intermittently and randomly. It does ping when this happens and I can't get the truck to accelerate, but it won't stall. I can only get acceleration back until I come to a dead stop, it will idle rough. As soon as I get my acceleration back, the truck will buck for a couple seconds and then go for a while without issue. I replaced the fuel filter hoping this would fix the issue, but it didn't. I was also smelling fuel during this time.

I can't easily get the truck to reproduce the issue, but it has been getting worse and more frequent over the last few days. Initially got a code for the MAP sensor being out of range.

I replaced the map sensor, it didn't initially fix the problem until I ran the self test - I didn't get any new codes and the truck seemed to run okay after the self test was run for a a few days. The fuel smell also went away after the map sensor was replaced. After a few days the problem reoccured. I can run the engine self test again and pull codes and the truck will run fine again.

I don't seem to be storing codes in the memory. However on my last self test, I got codes 25, 38, 17. I am not really sure what direction to go, this doesn't feel like an ignition problem, it feels like a fuel starvation issue.

It seems to correct every time I run a diagnostic self test.

is your idle speed ok.

vacuum leak cause MAP problems. dirty MAF will cause performance problems. inspect and clean MAF and look for any vacuum leaks.

There is no maf sensor only a map sensor on the passenger firewall. There is no vacuum leaks the canister is also the plastic version not the the Metal Coffee can size and it wasn't leaking.

Idle speed by ear sounds fine, it idles fine and happy. However, I don't have a tachometer on this truck.

I pulled some new codes last night.

116 - Engine Coolant (ECT) sensor out of range – ECT
63 - Throttle Position Sensor (TPS) signal too low TPS
61 - Engine Coolant Temperature (ECT) sensor is or was too low – ECT
14 - Ignition pickup (PIP) was erratic – Ignition Systems
55 - No or low (under 7 5 V) Key Power to PCM pin 5
86 - (M) 1 9L MFI – System has corrected lean condition – Fuel control
22 - MAP (vacuum) or BARO signal out of range – MAP
26 - Mass Air Flow (MAF) or Vane Air Flow (VAF) out of range – MAF VAF

coolant temp plays a very important part, I would start there first...

ford 5.8l operating temp is 95 degrees.

sensor will have two wires, one is the 5v reference the other is the signal wire. using a volt meter, KOEO, check for 5v on the reference wire. on cold engine the signal voltage will be 3.x volts depending on outside temp.

start engine and let it warm up. as engine warms up voltage will drop on signal wire. at 95* voltage should be around 0.55v. I would also check the actual temp of the coolant with a thermometer.

That's a whole pile of sensor codes, seeing that makes me think a power or ground issue. Check the 5v ref and engine computer power and grounds. An open or short in the wiring whis there there is movement, chaffing or heat would be be a good place to start.

That's kind of where I am looking now. I ran threw a bunch of therories because I didn't have codes and ran into dead ends on each.

I was trying to figure out why my truck ran better after I ran the diagnostic self test during the engine running diagnostic test. I am under the assumption that I was clearing the tables from memory when i pulled my jumper.

I think I have low voltage at the PCM, I will start by repairing the ground and check the pcm.