Just got a Craftsman GT tractor with a 22HP Kohler + 50" deck. Ran great when I got it. My yard is very steep and while my smaller tractor would run sideways on the hill, found out this one won't. Anyway, rolled over one time, gas + oil both poured outta filler necks until I got it uprighted. Started right up + ran fine for a few minutes, then started surging, missing, + even back firing out exhaust. If it sits for awhile, same thing, runs good for a few then starts surging again. Any suggestions, I really think this is due to it going over. Nothing really damaged, but it sure don't run the same.