SFD410

Hey all! 1979 F150 custom, 302, 3 speed C6 trans! Truck runs fine at an idle and down the road BUT when i stop and it idles in gear it idles very rough and wants to stall! Put it in neutral or park and it idles fine. I rebuilt the carb, did plugs, wires, cap, rotor, vacuum modulator on transmission, air filter, all new fuel tank, filters, and sending unit. Truck was sitting 10 years prior to all this work so I don't know how it ran before hand. Oh also it only does it after truck warms up. HELP PLEASE!!! Thank you!

JayzDaddy

Check to make sure the choke opens at warm idle. If yes id venture a cracked vac line

KeithMcK

Mine did the same thing. One of my vac lines got hot and had a small hole

Half ton

My 1982 f-150 had the same problem and mine also was discovered when i started chasing vacuum lines. MIne had a big crack in one of the lines on the intake.