Good Day,
I Have 1987 3.9L carburated, Dakota,, That has a weird problem,,, Most of the time it runs very good, dosent miss a stroke, but suddenly it will start to miss and loose power,, and it will continue like that until you turn the key off and restart the engine and it will run fine until the next time it decides to act up,, sometimes it will go 100 miles before it acts up and other time you can't get 5 miles,, but it is always the same fix.. Stop and start the engine...
Any Ideas..
I have replaced the plugs, plug wires , distributor cap , rotor, voltage regulator, EGR setup...I want to see what is under the rotor in the distributor, but the book (hayes ) is almost a waist of time to read,, I'll get the clymer book that should help...

 

My best guess is something that controls the ignition system. I'm not to familiar with the early years so I can't tell you for sure.