LOSS of MPGs

[sootlife01]

So i have a 01 F-250 with the 7.3 and when i first got it i put on a Edge w/Attitude chip, silverline exhaust, and a volant cold air intake. i was getting right about 20-22mpgs on the interstate and about 16-18 in the city and almost 600miles to a tank. now all i can get out of ol'red is 16 no matter where i go and when i tow anything with alittle weight it goes all the way down to 10mpg. i change my oil and fuel filter regularly and but treatment in my fuel about once every 6months but still nothing. Any ideas?????

[7.3HeavyHauler]

boost leak, exhaust back pressure sensor dirty, check ICP sensor, brakes stickin? just a couple things to look at

[eurotrashb5]

wow...i do mostly 60mph on the highway and average 14-15. Am I having some serious problems with mine? Brakes arent sticking, hopefully when i replace the fuel filter and clean the ebps it'll help...

[TD444EVER]

wheel bearing or front end issues causing drag? you can grease your hubs from the ABS sensor

[NoRalPh]

Could be the "Winter Blend" too...

For the cold, fuel is thinned at the refineries to prevent gelling during the winter months (was with Kerosene, now with ULSD I'm not positive it still is what's used). There's less power in the winter fuel, your mileage will drop (temporarily).