My 1999 F250 SD 7.3l has developed a severe surging problem. When the surge occurs, it completely takes over the engine, surging between about 600 – 700 rpm (as close as I can read the dash tach). Flooring the accelerator will not increase the rpms, and the vehicle has practically zero power. It won't move fast enough for the speedometer to show anything. The problem is intermittent, and at first seemed random. But there is a pattern, which I discovered after doing these things:

1. Replaced dirty air filter with K&N

Replaced fuel filter
A friend brought his big scanner, and it showed a bad EPM sensor.
a. removed the sensor and tube to clean them, and discovered a hole in the tube.
b. replaced the EPM sensor and the tube with new from Ford..
c. The engine still surged
d. disconnected the EPMV actuator rod, and opened the flapper.
e. The engine still surged.
The pattern seems to be that if I crank it when engine is cold, like having sat all night, it starts and idles fine for about 15 minutes, then it starts the surging. After it idles for 30 or 40 minutes it smooths out and can be driven normally all day long. If it is shut down for more than about 45 – 60 minutes (not exact) it will surge when started, and then you're stuck until the tantrum ends.
No CEL is set.
Have any of you been through this?


Thanks,
Sam

 

wrong area...

 

Thanks, I can see that now. Can I move it or just repost?

 

the moderators can move it i dont think the starter can...

 

Moved to correct forum.