Drop in mileage

Ive noticed my car recently is going through a tank of fuel quicker. I got it with 41K miles, now Im at about 69K. I'm thinking of cleaning and re-oiling the K&N I put on when I got it. Also some fuel injector additive next time I get gas, and replacing the fuel filter. Anything else I should check or do?? :shrug:
 
Its getting cold, when it gets cold air is more dense, it takes longer for the vehicle to warm up, combined it equals more fuel needed, more fuel being burnt, more power and unfortunately less gas mileage.
 
I agree with you on changing the fuel filter. Recharging the K&N is always a good maintenance step as well. Make sure you don't soak the filter too much in the charging oil, or it may get on your MAF sensor.