My Valiant recently began temporarily losing ignition power while driving. It doesn't just miss, it dies. It only lasts for a few seconds, so I suspected a bad firewall connection. Since all other electrical functions are fine, I concentrated on wiring in the ignition circuits. Cleaning bulkhead connector terminals didn't help, so I cleaned and tightened every connection that was ignition related, and I still have the problem.

The last time it failed, I didn't get the car in neutral as fast as I should have, and enough unburned fuel collected in the exhaust to blow the back off the muffler when it fired again. I really hate when that happens...

FWIW, I also have a NOS ignition switch that was installed a few months ago. The MP electronic ignition is also relatively new, and the orange box is from the days when they were US made. Even so, I'm going to install a new stock box to see if that does the trick. Just wish I could find one made in North America.

I love old cars, but sometimes the problems can be a real pain to track down...especially the intermittent ones.

…not really suitable for street use, unless you (thoroughly) rework the distributor's mechanical advance.
…has been not a very good unit since before they were sourced in China.
Can get from Old Car Parts Northwest.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

The distributor has stock springs and vacuum can from...I think it was a '79 slant. I reworked it a couple of years before I bought my car, so it sat on the shelf for quite awhile. I got the MP kit in a closeout deal for less than the cost of a new stock distributor and couldn't pass it up. It runs perfectly...when it's getting spark.

Thanks for the link to the good parts source!

Divide & conquer- don't guess at the problem, diagnose it. Get about 15 feet of small gauge wire. Connect one end to the ignition coil +. Run the wire out the back edge of the hood & into the passenger area. Connect it to the tip of a 12V test light & (solidly) ground the other test light lead/clip. The light should glow - dimly- while the eng runs. If the light goes out when the eng "cuts" out, (ie, you're losing coil power) then move the wire closer to the ignition switch & retest until you find the fault . If the light stays on, (ie, you're losing coil ground) then you need to diagnose the ignition system.

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63 Valiant Wagon
225 - 4 bbl

If it failed with any degree of regularity, that would be a reasonable idea, but oftentimes it goes for days without failing. For now, it only happens often enough to be annoying.

Intermittents are a pain in any generation of vehicle.

Your coil can also cause this problem.

Bulkhead connectors are always my first spot to check.

FWIW, I replaced the ignition module with a stock unit that is USA made. Since the coil was the original, or at least it was on the car when I bought it ten years ago, I changed it also. No more intermittent cutoff.

If the problem comes back, also check the ignition switch to harness connector; I've seen them overheat and make a poor connection sometimes.

Get rid of that Orange Box, those things suck. The one I had lasted three weeks and died.

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2