That "glitch" has been buggin me for a long time, but I feel better now. There's another one that involves the EGR error detection, but we can analyze that one latter...
This O/L idle sounds like the way to go. But we need to put some thought into how to best apply it. Now if we use the factory code, then the conditions for entering O/L Idle are:
1. Coolant temp > $3405 - C/L Min Temp (76 degF)
2. ECM not in ALDL Mode
3. BLM Cell Offset = 0 (using cell 0)
4. TPS% < $367D (1.6%)
5. adjusted MPH < $342E (0.3125 mph)
6. Integrator between $3430 & $3431 (122-133)
7. O/L Timer has elapsed (is FF but needs to be at least 01)
OK, so the original coder went to a lot of trouble to ensure the car wasn't moving and the driver wasn't trying to scare the Mustang owner next to him at the light.
I like the idea of 2 different AFRs because I'm thinking start the car with AFR = 14.7 and control fuel with existing tables. After initial warmup, switch to something richer, then use a 3rd AFR for norm operating temp. What do you think?