I have a 1979 ford f150 with a 351m I have replaced the fuel pump, the filter, the accelerator pump on carb, and i have blown out the fuel line with air. the truck will idle fine, when I go to press gas pedal the truck will die.

redneck; My first instinct would be the accelerator pump diaghragm. But, if you've already replaced it,.... With the engine off, work the throttle while looking down the barrel of the carb to make sure the accel. pump is working. These did have somewhat of an adjustment where the linkage attaches to the throttle lever. If everything is good, then, let's look at the distributor. Try disconnecting the vacuum hose to the vacuum advance. Plug off the hose and try it. It is uncommon, but when the distributor advances, it can lose ground (internally) and cause the hesitation.
Loren
SW WA

I dont know much about cars, but I had this EXACT same problem, it ended up being my distributor cap and rotor arm inside needing to be replaced, I swapped my Fuel pump, filter and all relays and way to much other crap, just to find out later its a $13 friggin part.

May not be same issue for you, but hope it is so its a cheap easy fix!

Good luck!

Greg

Yes, it is possible for that to be a bad coil, coil wire or distributor cap. They will fail under load if they have high resistance.




78 Corvette Pace Car For Sale-18k mi orig-Florida

My experience with this prob- same engine, turned out to be the EGR stuck open just a little. Fixed that for my future father-in-law (RIP) years ago. They then promptly stole the truck. Detroit Must've known it was fixed!