ive been getting around 200 on the tank this winter, in the summer i was getting over 300, i recently bought new tires and went from a 31" to a 33" tire, i went to one of those calculators and my speedo is off by two or three mph at the most, am i actually getting better mpg then it says due to the tires or not?

 

No you will get worse gas mileage with bigger tires period.

 

my new tires arent really that much bigger though, would they really make that much of a difference? or is it just from winter running, warming up the truckk and etc

 

You will see a difference from the tires, but you say your warming it up in the morning, if you wanna save gas thats a big No No, that kills gas, and yes you will get worse mileage from the winter air, but here are some tips to help you out.
http://www.fordf150.net/howto/fueleconomy.php
Hope this helps

 

Just how does cold air temp cause you to get worse fuel milage? Cold dense air makes more power. Does'nt a modern engine moniter things like ambient air temp as well as intake air temp to adjust you fuel to get 15/1 air to fuel mixture in the winter and summer? Poor winter milage usually has to do with winter blended gas, warming up you engine, a cold engine is less efficient so warm the engine quickly by driving it not by idling it for 20 minutes, low tire pressure and poor aerodynamics from stuff like snow and ice on your truck. People tend to drive slower over the winter due to road conditions and the fact that there are fewer hours of daylight. It all adds up.

 

Depends on how cold the air is I don't know exactly the stats I'm sure you could look it up but theres a range where any vehicle is running the most efficient. So not to hot not to cold. And our motors are electronic fuel injected, start em up let the idle go down and your good, your trucks computer adjusts all the time to conditions you don't need to warm it up. It's not 1975 where we all have carbs. Oh and yes winter blended gas is worse

 

I wish mine had a carb. Easier and cheaper to work on. I'll tke a 351 Clevland and a 4 barrel over a gutless Triton any day.

 

i hear you on that one, carbs are s easy!

 

cold air is more dense so you need more fuel to maintain a/f ratio. In adition when the combustion chamber is cold (warmup) more fuel is required. Oxygen sensors with fuel injection is much more efficient than the old carbset up with the auto choke, also less drivability issues. Probably can make more power though with a carb set up.

 

I wish it was 1998 and gas was 70 cents a gallon so I did'nt care about fuel milage. We should nuke the middle east and destroy opec! Devide all the oil between the U.S. and Russia and China and call it a day.