I bought my son an old farm truck for his first and because I like F150's. We drove it home with a real rough idle and poor porformance...I expected a good tune up would help. Well, we can barely get it started and haven't driven it for weeks. It blows black smoke out when cranked and will not start. I replaced the pluges, wires, distributer and cap. It ran for about two days and acted up again...black smoke and all. Pulled the plugs and they were fouled. Put new ones in and it ran for a day - now back to black smoke upon trying to start. What is going on!!!

 

to much fuel... is it carb or sfi?

 

It is fuel injected. I've replaced the fuel pump recently.