I own a 335i E90 N54 auto here in Brazil.. It has AMS DP, K&N inbox, COBB, and AA BOV .
Everytime I change my current map with the cobb system, the car seems to be stuck in 2nd or 3rd gear for a while, and suddenly it drops to 1st after a few ft of driving and everything stays normal.
This only happens right after I switch the map, when I turn on the car. And only one time every time the map is switched.
Also, if I select Reverse before the car has dropped to 1st, there is a big CLUNK noise coming from the transmission.
Why does this happen? I cant seem to find any plausible answers on Google or any other source. Also, the car missfires a little bit in its first start in the morning.