~Erik~
2013 Sonic RS Manual - 1.4L I4T E78, tuned, turbo mods, etc.
2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.
I honestly don't know. Paul might know. Maybe there is some additional use of the other memory locations. Say VIN or CASE Learn or LTFT values or maybe even ASPARK values.
Not sure completely, but IIRC the "1MB" PCM's have 28F800's too, so maybe the PCM supplier got good prices on it that way, or maybe there was a problem with the supply of 28F400's so they had to use 28F800's. No way to know at this point.....
I owned a Ford once, ONCE.......