1989 Jeep Wrangler Stalling

Engine Mechanical problem
1989 Jeep Wrangler 6 cyl Four Wheel Drive Manual 66k miles

Jeep is driven once in a while, last year I had a problem with the jeep back fireing and them losing power, statring to stall out, more back fireing and then the car would quit and would nmot restart for an hour or so. This jeeps tends to run cool, it did not appear to be over heated. Shop had me replace catalytic converter, problem persisted, they changed a computer part, winter came and I don't often drive it in the winter so I had no problem. Last fall it happened several more times, different shop had it for several weeks letting it run or driving it around but could not replacate the problem. They rerouted some vaccum lines and checked out the fuel filter and some other stuff but it did not stall while they had it. Now its summer again and it did the back fireing thing againg the other day. Car stalled, I left it for an hour and came back and it started up and I drove it 1 or 2 miles home. Any suggestions?