xsk5

hi all, i've had autotap since 2002 and i'm barely learning how to use it. i was checking the A/F ratio on my 97 tahoe and noticed when i first turn it on it's in the high 13's to low 14's. then after i start driving it drops down to 11. is it supposed to do that? it's stock except for a K&N filter.

sorry if it's a dumb question but i'm barely learning how to use it.
thanks for any help

andy