I have 1990 jeep Cherokee 4wd with a straight six and automatic transmission. This has happened a couple of times if my jeep sits for awhile it wont start. The engine turns but it wont fire. I put a inline spark plug tester and it showed there was no spark. I tested the tester on another vehicle and it worked. I mead with it for awhile run battery down hook it up to jump and let it charge still no spark. I leave it alone for awhile then it will fire. A couple of times it happened when it had not sat for awhile. The cps has been changed along with distributor coil cap rotor plugs and wires. Haven't had battery checked but seems to crank engine over without a problem. Could it possibly be the terminal connections are loose or dirty. The next chance I get I'm going to get battery tested. Any thoughts onwhat route To go down. Once I get it started it runs normal and starts normal after. To add this morning it happened I popped the hood wiggled about every connection I could then it started.

 

You may want to freshen the contacts on the ignition control module (located under your coil).

Cruiser54 has a writeup on this somewhere. SEARCH for it.

 

Found it.
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The contacts between the coil and the ICU on your Renix Jeep can become corroded and loose causing a complete or intermittent no-start condition. I recommend the following procedure as a maintenance precaution to insure this is eliminated as a possible cause now and in the future.

The coil is attached to the ICU by two T20 Torx bolts. Remove these two bolts and lift the coil up off the ICU. You will see 2 pins and 2 sets of contacts. Clean both the pins and springy contact pieces with a good electronics cleaner.

Squeeze the springy contacts closer together with some needlenose pliers. Apply some dielectric grease to the contacts and bolt the coil back on to the ICU.

While you’re right there unplug the connectors from the ICU and inspect the pins in the harness connector. Make sure the pins are not retracted into the connector. Spray out the connector and the receptacle of the ICU with the same good electronics cleaner you used earlier. Apply dielectric grease to the connectors and plug them back in.

 

Thank I will try that