stalling with no warning

[mab6680]

hi i have an 88 wrangler with the 4.2 and a 5 speed trans it will just stall with no warning and start back up when left in gear it happens mostly at highway speeds but also happens at lower speeds from time to time i have changed the fuel pump, coil, cant the of the name of it right now but its the black box in the distribtor any help would be great thanks