Used to always get 300 miles per tank of gas, now getting 250.

Happened after i did 3 things in one week so i dont know which one caused it, i fitted new tires Yokohama Geolanders 255/55/18, installed a KNR intake filter (filter and bend connected to the flow sensor) and finally had a new final drive assembley installed in the rear diff under warranty (which still whines a bit but its their 5th attempt at fixing it...long story)

I've tried with the power button on and off, doesnt make much difference. 15mpg was bad enough but now getting 12.5 to 13 is hurting the wallet some,

any suggestions?

Pete