Easy shifter....one variable at a time.
The accel pump, if that is what your are referring to is only needed if you jump on it and need a little extra fuel until the venturi can catch up. With the truck off, look down the carb and make sure your linkage is moving the throttle plates that are inside the base of the carb. Check the sight glass on the front of the carb and manually fill it if needed. That will confirm the fuel delivery is or is not working to the carb. Ifin I had to take a wild a$$ guess.....your choke was not adjusted and it got sucked closed cruising down I-25 and effectively closed off all the air to the engine.