Jeep is running very rough hesitates,losses power,hard to start.

Hello, the "check gas cap" message indicates a problem noted with the evaporative emissions system. This will require hands on diagnostic testing, utilizing a diagnostic tool that can monitor the performance of this system's components. No, you should not use a Chevrolet truck fuel cap for your Jeep. This is not why you have a running problem though. That's a different problem. Your engine performance issue is likely due to a concern with fuel delivery to the engine, air to the intake manifold or ignition spark. You could also have another emissions system concern, such as with EGR operation. Engine timing or compression should be checked also. www.repairpal.com/repair-shops