i have a 1980 ford f150 ranger with a 351M. when i start it up it sometimes will idle sometimes it wont and then when i start to drive it i will get up to about 35 45 mph and then it starts to cut out and dies on me even when i give it gas......i have rebuilt the carb but on new spark plugs and spark plug wires, ignition coil, mechanical fuel pump, and a new rotor inside the distributor, and new distributor cap.....gimmie some ideas on how to fix it

 

Is the egr valve opening up prematurely? Or is it already stuck open? You can tap on the base of the egr with the engine idling and see if the idle improves. You might have carbon stuck in the port on the valve.

 

i figured it out i had a push rod that fell down into my engine on my third piston