Wish I could help, but I'm as stumped as you are. Sounds like it could be a timing issue, but you still should be getting some intermittent fires. Plus, it was running fine when you shut it off...?......that makes no sense to my mind, other than the previously mentioned CPS (or some other "computer-related" sensor). The computers and the sensors (electronics!!!! :shock: ) often leave me dumbfounded. Hopefully, the others here with more knowledge can help you (and me) out. Best of luck.