Runs for about 20 miles and then cuts off. let it set for about 1 hr then startsup again please help. 88 ford bronco 2.

Check your fuel lines, check the filter for clogging, check the fuel pump and finally when the car stalls check the fuel and ignition to confirm.
Once confirmed replace or rectify and test run again.

Ignition module on the distributor is bad....
you can check it by starting the truck and letting it run while you heat the ingnition module on the distributor up with a hair dryer... duplicating the time running x 20....
If this turns the truck off... replace the module... and carry an extra along in the glove box if you take any long trips...