1994 Jeep Grand Cherokee Engine code

The fault code did not say the injector was bad or to replace it. Diagnostic fault codes never say to replace a part or that one is bad. They only indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. This is especially true when you have an intermittent problem like this. There's no way you would ever know where to look without that fault code. For this problem, the most likely suspect is a stretched or corroded terminal in a connector, or a wire going to it has rubbed through and is grounding to the body intermittently. Try wiggling the wire harness while the engine is idling to see if you can make the problem act up.