I have a 2006 Softail fxst and I just did the 20k service on it. After I finished I went to test drive it and my check engine light came on. After reading your article on TDCs I pulled codes and found P1353 and P1356. On the service I changed the plugs and wires with screaming eagle plugs and wires. I told the guy at the Harley Dealership that I had stock compression, so he gave me the plugs for that engine. Could the plugs have something to do with it? Code P1353 and P1356 say no combustion in front cylinder and rear cylinder.