Sounds like a connection is getting hot and going open, commonly refer to as a high joint in electrical trouble shooting.
It could be in the ignition switch, the wiring in the steering column or in the instrument wiring harness to the bulkhead connection or in the engine harness under the hood scope wrench
Do you jiggle or touch and move any of the wiring when it quits? If so try doing only one thing only at a time until you can figure out exactly which circuit or wire is causing your troubles scope
Good luck up
Please let us know what you find luck

Last edited by Cab_Burge; 08/23/22 12:11 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)