I have an 87 F-250 with the 300 inline 6 that is driving me crazy. Two weeks ago I needed to move it and it would'nt start. Replaced the fuel safety switch and fuel filter and it ran fine for a couple of days. Then it acted like it ran out of gas. Left the truck for a couple of days and it started fine and ran good. Now when you start it, it won't idle, it speeds up and slows down until it stalls. Once its warmed up it idles at 2000 rpms. Any ideas?

 

Kohn,
How long had the truck sat around ? Cold climate ? What was it running like before this ? I was thinking if it had sat for an extended period the gas may have become a little skunky .
Paul

 

I had the same problem with my 87f250
and i was walking before i found the trouble
hear it is! there are two relays next to the
air cleaner assembly one of the wires in the
plug (bottiom) was corrded in half.loss of
contack would stop power to the fuel pump
makeing the truck seem like it was out of gas.
this is how found it.with key on by moveing the
wires under the relays you can hear the fuel pump
trun off and on.
if the wiers are good,tap the relays on the top
listen for the pump to turn off and on.
last check and see if the relays are warm or hot to the touch.

 

This thing feels like its running outta gas when you try to accelerate over 20mph.
It will do 65, but only downhill.
Scopecheck is clean...and come to think of it,
when I used to switch to the rear tank, it would spit and sputter, so now its happening on the front tank.
Fuel pressure and volume is great at the rail,
Could it be the tank switch?
'86 f 150 60k miles, automatic.
just dies with full throttle, but will creep up to speed in a few minutes.
THANK you all