Hi all I have a 1990 F350 with a fuel injected 460, zf5, borg trans, etc.

When Im driving sometimes for what ever reason the check engine light will click on. My idle issue is irregular and tends to happen when it is only cold out. 40 and below'ish. This problem only happens every once in a while somedays it doesnt happen at all. If I shift to hard sometimes it throws the check engine, every once in a while the light turns off when driving.

Heres what it does, it tends to start as im driving for a long time. over ten miles, I'll push in the clutch and it'll run over 1100 rpm when coasting to a stop. Sometimes higher. When Im shifting it'll rev to 18 or 1900, when Im getting off the freeway it stays at 2000rpm till I have slowed below 30 miles an hour. It will stay revved up till you slow down.

It has coolant in it, oil all that, I cant find any bad connectors or sensors and the only code it throws is for the sending unit in the tank (doesnt work), and for this valve I dont remeber what code, but for a sensor that has the pvc line hooked to it and some wiring on the valve cover?

One code was 96,
(O)
Fuel pump monitor circuit shows no power - Power / Fuel Pump Circuits


(R)
AIR Bypass (AIRB) not working - Air Injection


(M)
(Service 87 code first if present) Fuel pump relay or battery power feed was open - Power / Fuel Pump Circuits

I did have to replace the fuel relay and tap into a line at the relay and run a NEW wire to the fuel pump to make it run. They refused to turn on before and had zero voltage. I dunno if that has anything to do with it, the problem still existed before that modificatoin.

thanks for the help and reading my long post! matt