I decided to replace my spark plugs from TR55 gapped at .045, to a TR6 at .035. Didn't change anything in the tune and I noticed my AF on the widebands went from 11.3-11.5 range to 10.5 WOT with the new plugs installed. I went in and cut the %change to WOT fuel down a few percent and I'm now reading in the 11.5-11.7 (need to richen up a touch).

I'm assuming with the colder plug/smaller gap there is extra unburned fuel, and that's why it richened up on me. Car seems to run a touch stronger, but weather has been cold lately which makes the tires easy to spin. Am I on the road to KABOOM, or am I actually on the right track here? Old plugs looked pretty good, but i'm assuming the wide gap,hotter plug, extra fuel increases cylinder temps for easier detonation.

Thanks,
James

 

It's possible that you're getting an incomplete burn.

Maybe you got your gas somewhere different - Some of the gas has more or less ethanol content, Otherwise, maybe the colder weather is doing it. You also have temp tables in the enrichment setup which could do it if you are running cooler. If you suspect the plugs, you could put the other ones back in or change the gap just to check your theory, although that is a pain to do.