Cherokee revs up wont start - 1990 Jeep Cherokee Limited

Your description is too vague to give specific advise. However, if you are stating that the engine turns over when you turn the key but it wont run, then you want to check a few possibilities. Fuel, Spark, compression. Make sure the engine is getting fuel. Then check for spark at one of the plug wires. Then check cylinder compression. No fuel can be a fuel pump, plugged filter, or pump electrical connection, like pump relay or wires. Spark problem can be ignition coil, coil pack, distributor module, distributor points. Compression can be piston rings, valves, head gasket. This is not everything, but it may help you!