I have a 96 Jeep Grand Cherokee limited and yesterday I went to start it and nothing it was dead. Jumped it and ran pretty rough then idled out. It will start but will not stay running. after letting off the gas the idle runs really low and it dies again. I checked the battery put in new plugs cap rotor wires air filter and even changed the oil but is still stalling out and running really rough and now it is backfiring! Does anyone know what my next step should be short of taking it to a mechanic? I was thinking maybe the o2 sensor is that possibly the problem? I know a little about cars but not enough to figure this one out... please help??!!