I had a big face tach back in 1985 in my Big Block Dodge Charger.
It had a built in Rev limiter, and while driving around the car just started shutting down.
At first I thought the fuel pump was vapor locking.
But after chacking that out it was not the problem, so I disconnected the tach.
And it stopped cutting off, so I opened the tach and found the board in that was cracked.
Just like the other guys on here said about yours. It really sucked because I had built
a whole floor concel around the thing with speakers in the sides and a couple cup holders.
Kurt