I have a 1988 f150 custom with the 5.0 in it. When I'm trying to accelerate it'll bog down and sometimes make a clunking noise until I release the gas then it'll run fine again. What could be the problem?

 

Grab a can of carb and choke spray, start your truck and while its idling, spray around vacuum hoses, egr pipe and base of the carb. If the engine idle increases where you sprayed, you have a vacuum leak. Repair the area, then move on. Keep on doing this until all leaks are fixed, then its time to take the carb off and rebuild it.