My check 4wd light came on then my 2018 jeep compass started misfiring like crazy. Hooked a code reader up to it and got misfire on spark plug 4. So I changed all spark plugs,which were all basically black. The jeep ran okay for a few minutes now its back to jerking like crazy. A day ago it didn't even want to start, the dash showed check ecm system etc light and yet again serv 4wd. Now the only light is the service 4wd and its running awful. Had anyone else had these issues and figured out what it is?