Keeps coming back after several repairs

It may be a misfire on cylinder 7. Check for a vacuum leak, including with the brake booster. Using a scan tool, check the short-term and long-term fuel trim readings. Your mechanic by now has probably checked the wiring, injector, and PCM--I'm assuming they are fine. Only use Champion plugs in your Jeep--the exact same ones that originally came in it. Replace them if they have 40,000 miles or 3 years on them.

If the problem persists, and the injector has been replaced, focus on the PCM--the #7 injector driver may be bad.