I have a 94 dak with a 318. It drives for 2-5 miles before starting to miss and then runs fine for another couple miles after turning it off for a minute. It can idle for hours without a problem.

Tried coil, plugs, cap, rotor, and computer from other truck and nothing changed. I noticed today that the volt gauge on the dash was reading high and the voltage at the battery was 15.2 volts at idle and 15.8 volts at 2000 rpms.

Could an overvoltage be causing my problem? IIRC, the voltage regulator is in the computer and should have been fixed when I swapped them.

 

Merry Christmas

Well, the over voltage definitely sounds like it could be the regulator, which is built into the alternator. Some auto parts stores, like Auto Zone, can check your alternator/voltage regulator for you.

I didn't see plug wires in your list. They can certainly be a suspect when you have a miss, especially one that happens only under acceleration. Normally you won't notice anything at idle, but if you accelerate hard the wires will begin to short out, causing the misfires. Whether the stepped up voltage can damage components in the ignition system, I'm not really sure.

 

Plug wires were also checked. I'm starting to think the coil can only handle the increased voltage for a short time before causing problems. It killed 2 junkyard coils completely, while the new one can recover from it. Once the misfiring starts it misses even at idle. Maybe it can handle 15 volts but not 16. I'll get the alternator checked after the holidays. I could use a bigger alternator anyway since I have subs and a winch waiting to go on.