Hey everyone. I have a 1982 F-250 that i have slowly been resurecting over the past year. it has a 351W,c-6. Ive since put in a new rebuilt 351, just had the c6 Rebuilt. It also has hooker pro comp headers, Edelbrock performer intake and a holley 600CFM 4bbl. Now for the problem. I have been having one problem after another with this truck. It ran like crap about 2 months ago and i had the stock intake replaced cause the EGR valve was acting up. Then the Carburetor went and put a new one in. The truck went fine for about a week after that. Then all of a sudden on a warmer day it was probably 65 ish and early spring i was going down the road and the truck started bucking. but it didnt do it constantly its on and off. If i look at my tach it goes way up to 3-4k rpm and drops back down to normal when it bucks. I thought it was my tranny going so i had it rebuilt :/ waste of 1grand right there. But now its still doing it. I tested the ignition system and its not getting a constant spark. ive replaced the ignition module it still does it. Ive replaced the coil as of today and its still misfiring. It seems to only do it on hot days and when the engine gets warm. I will be driving down the road and it starts bucking and it goes between running on 8 down to almost 4 cylinders then back up to 8. and when the engine gets warm it wont hold an idle and it jumps around rpm wise if i keep my foot on the gas to keep it running. I have tryed to describe this as best as possible and need any help i can get. Its a duraspark II system. I am running out of ideas on what the hell is going on. Please help Thanks

 

I would check your Dizzy maybe bad rotor or cap

 

I checked the Dizzy and rotor and cap contacts are all fine. As i said before the truck only does it when its warm outside 60+ and when the truck has been running for 20+minutes. And its intermittent and does it for a few minutes then stops for a few seconds and starts up again. Its very weird.

 

dID YOU CHECK CHECK THE CONTROL MODULE THEY CAN WORK FINE WHEN COLD AND FAIL WHEN THEY WARM UP THATS WHY WHEN THEY TEST THEM THEY DO IT SEVERAL TIMES IN A ROW SOMETIMES ITLL SHOW GOOD THEN WHEN YOU RETEST A COUPLE TIMES AND IT WARMS UP ITLL FAIL

 

sounds like it could be a control module or a coil.

both can run fine when cool, then fail as it warms up.

 

the control module was replaced first as they are known to be intermittent. and i just replaced the coil the other day and its still doing it. Its the weirdest damn thing and its driving me insane.

 

just a hunch i have but wire the choke open... i had a problem with a 68 mustang that no matter what i did the choke would fall shut, it would start up fine, i would go down the road and do 55 then all of a sudden it would buck and carry on and i would have to have my foot to the floor to keep moving.. it was real bad, sounded like it was cutting out... i blocked the choke open and that fixed, i went from there and finally got the choke straitend out.

btw, my dad and i thought it was ignition too with my car as we put new points coil and so on and so forth in it. i honestly would try blocking the choke open.

 

Hope I'm not repeating myself, I had an 82 F250 that would just crap out like someone turned the lights out. Ended up being that module inside the distributor. Parts store wanted more dough for it, than a new distributor! Also, check your wiring harness that runs on top of the fender, Ford had an issue with the soldered connection in the 80's and the factory insulation would wear in the area of the fender causing shorts. Hope I helped some.

 

I had an old 4 cyl car that was carrying on the sme way. Turned out to be a faulty set of points (in the dizzy). My 2 cents says give that a go.

 

Well i seemed to have fixed the problem i hope it seemed to be my spark plug wires. I replaced the stock ones with some Accel super stocks and it hasnt started doing what it was doing yet. ill wait and see its supposed to be about 90 out this weekend so ill drive it around and see what happens.

 

well i cursed myself this morning it started doing it again on my way home from school today .

 

if none of the before mentioned have worked, then I would guess it to be the pickup coil in the distributor.

 

but how can it only act up when the engine gets hot.

 

electronics are strange, but generally what happens is that as it heats up the break expands therefore creating an open, and when it cools, comes back in contact and works again.

 

i would seriously try blocking the choke open. It sounds like what my car was doing, we put new points, cap, rotor, wires, two sets of plugs, and it was the freakin choke fallin shut. it needed the other stuff anyway as the car had sat for 10 yrs but i just have a feeling to check the choke. if you examine the choke it may look fine, that means nothing, honestly try blocking it open.

and btw.... this problem was once the car was warmed up...i would start it up it would seem ok, i would get out on the road and get a few miles from home and i would it would just cut out and act like it was all messed up.