I have a '99 John Deere 425 AWS with a Kaw 20hp engine. Last year the thing started going through stints of runing rough. It only happened a couple of times at the end of last year. Starting this year the dang thing ran great, no problems at all until last week. It started it again and now seems to be doing it all the time. If I have the mower ingaged it loses power and shakes until it stalls. I can here the difference in the motor, it seems like it is missing. I have changed fuel filters and plugs, but it did not help. The plugs I took out looked fine and did not look like either of them were not firing. I was told to change out the selinoid that is on the back of the left side of the engine. It has wires going to both coils and the starter. I was told this was a cheap thing to try. Anyone have any other suggestions?