89 F250 4.9

[Burns]

My friend has a 1989 F250 2x4, 4.9 engine backed with a 5 speed manual. When he first starts it, runs fine. Shut it off and restart it before roughly an hour (or enough time to cool off) and it feels like it's running on only 3 cylinders. Runs like crap, and the only time he can get it to return to normal is to (if you're squimish, look away) is to bounce it off the rev limiter for 5-10 seconds. There are no check engine lights on, and the light comes on and goes out like it should on startup. Anyone else have a problem like this?

 

[DonnyG77]

clogged cat?

Did he do the normal tune up stuff?: plugs, wires, cap, rotor, fuel filter, air filter?

Maybe the EGR valve is sticky or non-functioning? It will run fine while cold, but run like crap after it's warmed up. I think mine is giving me problems. I have a 'bucking' at low RPMs that didn't go away after the tune up stuff.

If you find the problem, post it to give us an idea of what to look for if we have the same problem.

Good luck!

 

[lostin90s]

Sound like its loading up with gas and then the high rpms clean it out.

Clean the throttle body sensors and EGR . I'm not a 4.9 guy the 89 electronics for that matter