[96f150]

I know this is a mustang site, but I figured who knows the ford 5.0 better then the mustang guys. I just bought a 96 f-150 with a 5.0, 5 speed standard. It starts great cold and great when it is hot up to a couple min after you shut it off. If I let it sit 10 minutes it starts harder and if it sits 30 min it prob cranks for 5-10 seconds and then puffs black. I changed out the coolant temp sensor for the ecm, no difference. I I checked the fuel pressure with the engine cold it is 38 psi and 34 psi while running. The fuel psi does slowly bleed off after i turn the truck off, is there a rule of thumb for time engine is off to the amount of pressure that cam bleed off? Any Ideas?

[FastStang91Lx]

Black smoke is excess fuel. I would change the air intake temp sensor also.