More information...
Is the truck missing? Or stumbling like it is running out of fuel?
Is there any backfire through the carb (like a cough)? Or is it backfiring through the exhaust?
What is the compression on the cylinders?
What carb are you running? Is it a Quadrajet? If it is a Quad, have the shafts been rebushed?
Tell us all what you have verified thus far.
