Well, that IS a possibility with an AFR...LOL. It is just easy insurance when you start to push things. (Easier to read than plugs, IMHO, especially with the newer fuel formulations.)
Just concentrate on:
- Getting the AFR in the 12's at WOT
- Don't worry over a 14 or 15 AFR at light cruise
- Don't fret if it reads off when the engine is cold; it will be inaccurate as long as there is ANY liquid fuel in the intake mixture.
I'd move onto 93 octane if you can get it. The 91 octane that guys are limited to on the west coast and some other places seems to be more problematic for compression and ignition timing, based on some discussions here. Understood on the non-ethanol being desirable to avoid the gelling crap.
