20 Most Recent 1986 Ford F 250 - Page 3 Questions & Answers

My 77 Town Coupe had 2 as well. I never did figure out why either. Probably just something they added thinking it was a good idea.

Will it hunt for idle if you unplug the idle air bypass valve ? It could be a vac leak or something with the valve.

Check fuel filter and fuel pressure or a blown fuse.

clibrate the fuel sender lever with the gague level

you have a vac leak or broken plastic line . ck from the firewall where the heater hoses go in there should be a plastic vac line possibly red trace its path to the upper intake plenum I also think it has a vac canister looks like a can food comes in located on the fender well

Check your starter solenoid. I recently had a similar problem with my 1989 f-150. What ended up being the problem was the connection from the ignition switch to the solenoid (see image below).Make sure that is a secure connection, without any corrosion, dirt, or debris. This connector should pull straight off with some resistance. If the connection is sloppy loose (happens over time), then take a pair of needle nose pliers (or an equivalent), and squeeze down the connector just a little bit so that it has an oblong (oval) shape to it. DON'T OVERDUE IT. It only needs enough to keep it holding itself securely in place.Hope this helps, If this is not the problem, I'm pretty great with fixing older ford trucks. Reply back to me if this is not the problem.

flip the air cleaner cover for more air flow change plugs and wires , replace pcv valve cap and rotor if still not fixed you might have to get the carb rebuilt if it is 1st year fuel injection spray injector cleaner in and add a can of fuel cleaner to your tank

Check the battery. Any drain that would pull 20 amphours should spark terribly when you attach the battery cable. Fully charged battery usually 80 amphours+.The Alternator diodes could do it, a grounded starter could do it. You have a truck, but rear window defrosters could pull down a battery quickly. Stuck Relays like the fuel pump, a bad ignition switch where nothing really cuts off when the key is removed. Shorted trailer plug.Hope my solution helps you.

should be where the spark plugs normally are or they are in the intake manifold