Ok, this may be a stupid question but I am not very mechanical. Lately my 07 FXD has started occasionally sputtering and backfiring (and sometimes almost "dieseling") on start-up AFTER it is warmed up. It starts perfectly when cold. I would say it does this 1 time out of 10. When it started I thought maybe because I had just used 87 octane, but I have since used nothing but high octane. I can't seem to narrow it down to any particular thing that causes it. I am even wondering if it is something to do with a malfunctioning Power Commander III. My bike has about 15K miles, and was tuned and serviced at about 12K.

I have the PCIII, SE mufflers, and a SE 103 stage 2 kit installed if that makes any difference.

Any ideas or suggestions for me? Thanks