Could be the crankshaft position sensor. On a 1993 Jeep it is located on the transmission housing, drivers side, near the top. The connector sits on top of the intake manifold. Some auto parts stores carry them, others don't. Also, check the spark plug wires for arcing, even if they are as little as a year old. They go out more often than you would think. Replace if they do. If nothing then try replacing the distributor rotor, checking the distributor cap as well. All really cheap stuff.