Hi, I own a 1984 Ford F150 4x4 300 inline six 4 speed. A couple of days ago i went to pick up a snowmobile, and my truck had no power. I can not get pass 45mph. When the truck is idiling and a step on the gas it just starts cutting out. When i am going down the rode the truck also misses real bad. When i shift to 4th gear and try to accelerate passed 45mph the truck won't go and just stubles. It has stalled on me a few times at stop signs. Tharb idle speed is set at 900 to 1000 rpms. I have replaced the fuel pump, spark plugs, wires, distributor cap, and the rotor.
Thanks for your help,

Ryan

 

Did you change the fuel filter? If it has a little inline can right before the carb replace it with a see through one. You can then rev it by hand and see if the fuel level drops under higher speeds. Also can see if you are getting water up there.

 

Forget to mention that i also replaced the fuel filter.

 

Guess you're screwed. Truck is junk. Sell to me cheap.
Follow your fuel line back to the tank. Could be 2 filters. Happened to me once. Someone had added one underneath. And if it's hidden it doesn't normally get replaced.
Aftermarket fuel pumps are known to fail at a somewhat greater rate than you would think. Could be that. And make sure all your connections on the fuel line are tight. And here is a sneaky one. Pinhole in a line on the suction side of the pump so it is sucking air. Older truck, rusty lines underneath running by the frame, it happens often.
Or it could be something else. Good luck!

Lynn.