Thanks, Bill - makes perfect sense to me. And, I can see how your A/F curves smoothly adopt that strategy, rather than having the sharp "bump" at 4500 rpm.
But, now I've started "thinking" again (which I know is dangerous). The stock curve seems to hold the A/F ratio near 14.08 (the ideal for E10). And, I have to imagine the older trucks like my 2005 and earlier tried to hold it at 14.64 (for REAL gas
), so did Ford put out a flash to the PCM to "adapt" them to E10 when it sort of became the "standard"? As I recall from the f150 forums, the 2004-2005s were already lean running when they came out. E10 would just make things worse, right?
- Jack