Recently while wheeling my wife was attempting to climb a small hill. Approach and getting the front tires on were no problem but when it came time to get the rear wheels moving up is where we ran into problems. She stalled it several times by not giving it enough gas and dumping the clutch too quick. On her third or fourth time she gave it a ton of gas and didn't let off the clutch at all. The jeep stalled and when I tried to restart it had to turn over four or five times to get going and then the check engine light was on. I realize this is rather vague. Could it be an O2 sensor or what. Thanks for any advice.