Check the wires to the ignition coil. I mean pull on them.

Also, check to make sure the battery clamps are tight. And pull on the wires to the battery.

It sounds like nothing serious, but rather a loose wire somewhere in the battery-coil connectin.

I had something similar and it was the battery connection. But not from clamp to post, but from wire to clamp. The connection had an ever-so-slightly loose connx and ever-so-little corrosion on it but it was just enough to get it to cut out ocassionally. Cleaned off the copper, changed out to a flat-clamp style of post clamp, put on anti-corrosion spray and hadn't had a blip since.

PS - Many thanks to Joe Wicked for my actual diagnosis. I'm just passing on what was found.

As I said, do the simple resistance check on your MSD ignition module. (400 to 1300 Ohms) is the correct range. The ignition module does not necessarily fail catastrophically. It failed on mine intermittently, duplicating the same symptoms you have. I did a web search and it's a v-e-r-y common failure.

Dave

I had this happed 3 times and everytime is was the MSD box. I had a hell of a time finding it the first time because it would start and run fine untill the next mishap. I talked to many others that run the MSD and have no problem and some that do, I am one of those that DO so after 3 MSD boxes I have now changed to Mallory

Get a $20 water filled fuel psi gauge from Summit and mount it with a tee directly on the fuel line by the carb. I would not push the motor for fear of not cutting OFF fuel but running very lean fuel. But it's always good to monitor fuel pressure. Do you have a voltmeter ? When the symptons appear connect it to your pump on/off switch. If that's good perhaps remove your ignition switch and check for 12V output there too. I once had a broken ground wire to my external electric fuel pump give me intermittant PIA problems. More seriously a few years later I had intermittent idle stalling and finally a 60mph dead stall on the highway. I did ALL the electric checks and found no reason why my fuel pressure gauge dropped from 6.5 to 1-2 instantly ...then at times back up to 6.5psi. Eventually I replaced the fuel filter, pump, regulator, blew out lines looking for obstructions. Nothing. I dropped the tank and found a loose fuel pick up baffle which could slide a bit sideways. The fuel pick up/float looked okay. I ordered a replacement tank for $100 but STILL at idle in my garage at a steady 12V with old tank at half full........2psi. Now it was not even rising. As I was swapping tanks I started to very closely inspect the fuel the pick up line. I noticed a very fine hairline CRACK on the higher portion of my fuel pick up line. BOOM. That was ghost I was chasing all along. If you have voltage drop your task is clear. If you have 12V everywhere yuo might try buying another $20 Summit fuel gauge, attach 2 tees and a foot of fuel line to each side. You could try starting backwards with psi checks at the top of the tank. Work your way forward section by section checking psi with the handheld gauge. Hope this helps.

Intermittent problems are always a pain. A few things to check for as well, is to pay attention to when it happens. I had an issue where the motor would cut out in my old T/A only when it was 90° or hotter outside. Let it sit for a bit and you were good for another 30 min. Had to do a road trip from San Diego to OKC in it in July. Long day. I did not get to Arizona until 8PM. Turned out to be a clogged fuel filter.

Miles' problem was diagnosed because it happened when he hit bumpy areas in the road in Austin last year. That told me it was definitely a connection issue. It was causing fuses to blow, so it took a little run down and an issue that morning proved fateful as it led us strait to it. Little things like outside weather, road conditions, and other things that may not seem like they would matter are often the key to finding electrical issues.