After changed valve cover gasket, Poor MPG

[Amosus]

I have a 2011 328i xdrive. Its MPG is always 22.1, but after I changed the valve cover gasket a few weeks ago, the MPG stays to 20.2
Did I do something wrong?
When I changed the valve cover gasket, I was confused about how to remove and install the Valvetronic Actuator (Servomotor). I somehow installed it after watching a few youtube videos. The car runs smooth as before, but poor MPG. Is it due to the Valvetronic Actuator?
Please help

[gusm325]

Where are you in the US?
Running the A/C much? Hot there lately?
I have a stick but usually do 24-28 MPG, Its just my drive to work...
If the car runs without codes and smooth, I doubt valve gasket is the culprit, but the Gurus here may decide.

[Amosus]

No, not running A/C much.. No codes, very smooth. Just bad MPG...

[doclees]

Gas mileage drops significantly when the wife has the car.

[gusm325]

Sounds like the wife drives it properly to me.
Lives and breathes between 3.5 and 5k RPM's
:alright