Jumping at lower rpms

I have had a large number of issues with distributors and these trucks and I will tell you that it is much easier to just get one with a lifetime warranty from auto zone and swap it out. Once that o-ring goes in that distributor it is pretty much gone. I will warn you though... it was hit and miss for about 5 distributors. Cardone makes one but they are remanufactured and depending on whether you get a Mitsubishi or a cheap crappy one will be the determining factor. I swapped out 4 of them until the last one which was a Mitsubishi and just with the tighter play on the gear below you could tell the difference.

Not sure who made the one I got but it fixed it or so I believe. It doesn't jump and jerk around anymore but there's still a slight mis in the first quarter part of the throttle. Who knows. I'll replace the plugs and wires even thou the wires look new and see what that does for her

Just another side note, but usually when the distributor goes it is time for a new fuel pump and filter. I went ahead and replaced the plugs with NGK's, new wires, fuel pump and fuel filter from Napa. All in it ran right around $220 but it was easier just to get it all done at once. A common symptom to let you know when your fuel pump is going is that it will start to hesitate when you run low on gas right below the 1/4 tank mark and she will idle a little rough at lower RPM when she gets warm. The fuel pump gets hot and starts to quit and that is your warning that you have about a week or two before you are stranded.

New distributor, cap, rotor button, plugs and wires.... still doing it in the same part of the throttle....

Oh an new fuel filter if I hadn't already mentioned that

So I just had to replace the computer on mine. It is located on the passenger side of the cab by on the kick panel by the door under the glove box. It was the original computer and they are notorious for going bad. Back in the day, they used cheaper capacitors and they fail over time and either leak or fail to hold a charge. I went to the junk yard and pulled one from a wrecked one and swapped it out at O'Reillys for a new one plus the $200. I did that for two reasons. The first is that the core charge is almost $200 bucks and the second is if it didn't fix the problem I would have returned it and gotten the $400 back since they would not have been able to provide me back with my original core. If that does not address your issue then I would say it is probably a bad distributor again.

I'm leaning toward coil pack or bent valve....

I really hope it is the coil pack.....

You and I both brother

Your truck only has one coil and maybe it could be bad. You might want to check your vacuum lines to make sure none of them are cracked or leaking. That is a really common problem on these trucks; the rubber hoses start to dry rot. You can use a can of either while the truck is running to see if idle quality changes. Spray around the base of the carb and along the vacuum lines.