Car shut off while idling in the driveway:

I planned on taking the car out this weekend for the first drive of the Spring. I wanted to get the engine up to temp and then shut it off for a few minutes and then test the warm restart. I just replaced the battery cable and wanted to see if it made any difference.

So I started up the car and pulled it out of the garage and while it was warming up, I had all of the lights on so I could watch and see if there were any charging issues while I cleaned out the garage. About 20 minutes later, I approached the car to get it in and pull it into the garage. The car just shut off! No sputtering, the lights were all nice and bright. It just shut off. I was suspecting a fuse but I noticed that all of the lights were nice and bright (just like if the engine was running), the electric fuel pump was still running, and both of the A/F gauges were still active, the dash lights were still on.
I grabbed my meter and quickly checked the battery voltage (with everything still on) it showed 12.53v at the battery. So then I turned the key off. After about 5-7 minutes of thinking about it, I leaned in and turned the key
(just to see what would happen) and the engine fired right back up just as quick as it shut off. The good news is, the new battery cable worked out great on a hot restart! So then I immed iatlely pulled the car back in the garage and shut it off.

It appears that the battery, alternator, fuel are all in good working order. I am assuming the since the car was idling, the ignition must have lost voltage. But it re-started like a champ and the ignition box had a solid red light.

I plan on chasing the wiring from the MSD Streetfire box back to the battery. Then follow the RUN wiring from the box back to the steering column.

What else would you suggest to look at? (Ignition switch shorting out?)

Thanks!
Dave