I have been working on this truck three days.read the wiring diagrams checked voltage grounds.Just went through fuel system today.New plugs wires cap rotor.Runs like a dream for 20 30 minutes then tach drops starts bucking.nail it cleans up runs but below 3000 rpm starts bucking hard tach all over the place.tested coil it reads in limits still got spark and voltage.acts up for ten minutes then smooths out and runs great again starts its cycle over.eec seems to get wet when window leaks.but it does same thing when it dry outside.I open to any suggestions.just bought truck sorting out bugs and it had a bunch.window will be sealed and I about to take out eec check connections and look inside to see if there visable corrosion.anybody can give me a clue I would appreciate it.
Well I pulled the EEC out opened it up.Full of creek mud.Previous owner did a little to much 4 wheeling I see.So clean up the mud and corrosion with circuit cleaner put it back together see if that does it.
I would just get another unit. It sounds like that one has had it. See if you can get one from a junk yard.
__________________ Sgtsandman's Work in Progress 2011 Ranger XLT, 4X4, 4 door Super Cab. 4.0L, 5 Speed M50D-R1HD, 3.73:1, 8.8" open differential, Jason Pace cap 1999 Honda CR-V EX, RT4WD, 2.0L, 5 Speed MT, 4.56:1, open differential
thanks for the list but while you were posting I was working on it.It was the knocksensor circuit in the brain.Once it was cleaned out it started giving codes.Got another EEC and put it in problem solved.Truck across the street now instead of in my back yard owner very happy man right now.Odd thing was guy down the street stopped to look at the vacuum lines for his truck same model,and I mentioned we were about to head to the junk yard for a EEC and he says got it right behind the seat for 20 bucks.Done hand it over.So all happy ending.now we will be upgrading and fixin her up.
Randy. Take a look at my post 1986 missing and bucking--solved???
It might be worn throttle cable links, this causes the throttle plate to wiggle with the engine vacuum and the TPS sends bad signals to the PCM(computer).