Hello, I have an 86 f-150 that is old and needs a lot of parts I guess. For now it seems to be stalling/missing/backfiring. It has EFI so I can't adjust the timing. Not much of a troubleshooter so I need some suggestions. I just recently changed the alternator,fuel pump and filter, and put in the proper size battery. It has been doing this for a long time and its driving me nuts. 6 months ago I changed the plugs, wires and distributor cap. Also changed the throttle control positioner on the throttle body. When I start up the engine it revs really high for about 30 seconds then settles down but it sounds like the idle is to low? The truck has a lot of miles on it, I've only had it for a few years and it has sat in the driveway alomost all of that! I don't have the cash to gut everything and drop in a new 351W drive train set-up but that is on my list. All I want for now is to get it going. Suggestions? Thanks.
you say you have replaced the fuel pump, have you replaced the fuel pumps in the gas tank, there is one in each tank, the pumps get weak and the rubber gas lines in the tanks collapses. this causes a whole lot of new problems.
Try changing your ignition module..Common problem on these.
You really need to stop telling people to just change parts that you have a feeling about. Two words: Proper Diagnoses.