I have mowed some the pass two days with my new mower and have a question. After mowing for a while each day I have got off to moved some things and left the engine idealing. Before I get back on, the check engine light comes on and the engine starts to run rough and then dies. The first day I just waited a minute and start it back up. It ran rough for a split second and then cleared up. The next day the same thing happened. This time I checked the code and it gave a code of 31. It also would not start. I let it set for about 15 minutes an then tried it again. It started, ran rough for a second and then cleared up. I mowed for about 20 min longer and it ran like a champ. Any ideas of whats going on? Gas? Oxygen sensor? Low presure? Ground problem? Or maybe something I am doing.