[Hdpz2]

Its about inspection time , and everything i've put off taking care of has come back to haunt me. . .

P0128 - Thermostat malfunction
P114D - lean fuel trim in Bank 2
P0041 - O2 Sensor Signals Swapped Bank 1 Sensor 2/ Bank 2 Sensor 2
P0456 - evap (very small leak)

I'm ordering a thermostat and putting it in myself (first time I'm really gonna work on it)

The P114D fix was to clean the MAF (which i accidentally scuffed (left a mark) when taking out) but the code was pending again last time I checked. Should I get a new MAF or try something else ?

The P0041 fix seems to be simply switching the 02 connectors at the engine, but am I able to do it upfront near the ignition coils or do i have to actually get the tools and switch the 02 sensors underneath the car ?

The P0456 is the one that eludes me big time . I've bought two gas caps (updated ones with blue ring one from amazon one from bmw) and still showing, I read something about checking these 2 valves (blow through them and make sure air is going both ways) but i don't really know what to look for or where there located . any ideas ?

Thanks in advanced !
btw e90 330i 06

[Barebone]

P114D - lean fuel trim in Bank 2

It seems to me that the MAF is not connected with this error. Since the sensor is one, and the bank 1 and bank 2