I have a 2003 6 speed dually, it is the h.o. but it has very low power, very little black smoke, stalls at random and wont start back until it sits for a minute. otherwise the truck runs and sounds good. the lift pump is good so i unplugged the fca and noticed absolutely no change, does this mean my fca is bad or that the pump isnt working properly?

 

call in and talk to Sterling. He can help you with trouble shooting. # is in my sig.

Could be a bad lift pump, but there are a lot of things it could be.