its normal.. just a slight delay with the ecu, still giving you the same amount of fuel fro 12hg for that first half second or so before the vacuum gets to 20hg. same fuel, less air, gonna run rich..
*edit* EG8SIR is correct on the open loop, my bad on the type-oIf the O2 sensor is Disabled then he is running in Open Loop, When the O2 is Enabled he is in closed loop. Cruising at 13.5 afr's? that thing would suck gas so bad, cruise you want like 14.5-15.2 and Full Throttle you want 13.5
yeah, i'm running n/a at the moment, but the supercharger will go back on soon enough.No Big Deal, You got good info to share as well!