1977 F250
400M
C6

Ok here we go....

Ive noticed sometimes after letting the truck sit for like a 1/2 hr or so (after being run to operating temp), it wants to miss and stumble around. It idles fine but as soon as you take off it loses most of its power and it begins acting like its starving for fuel or spark.

It usually clears up shortly (like after a mile or 2).

On saturday it did this to me, and i played with it a lil, it would idle fine, bucked and hesitated in the middle RPM's, but if you slapped it to the floor it seemed to be alot better (but not perfect)....then it was fine again after a lil while.

I dont know if the issues are related or not but if your cruseing through town or whatever at 25-40MPH or so and you get into the throttle (not hard, but just normally), it hesitates, just for a second. It goes down in RPM then comes up. It does this all the time.

It does not do this if you floor it or if you or super light on the throttle.

Any ideas?

I rebuilt the carb but i was having similar issues before i did. Im almost wondering if it isnt in the ignition system somewhere?

With it being cold out now, my first look would be at the choke since it sounds like it clears up once warm. Another go to area for 'stumbles' to WOT is the accelerator pump getting worn.

I just replaced the Acclerator pump so i guess maybe its the choke. I notice sometimes stays at a higher then normal idle after a little bit of driving and when you hit the throttle and let off it goes to a normal low idle.....the choke is set completly to "lean" though.....

Could it possibly be a bad pulloff?