Ethanol,is a good point Dog! Also like the others sad Tire pressure is a big factor,if there was a big temprature difference from north to south your tire pressure could change alot,potetially causing bad milage.

 

^^^ Cold tire pressure is going to be the same North or south. When pressure rises from heat, that shouldn't effect mileage too much. Too low of pressure will result in bad mileage.
Tire pressure should be first on the list for long travels.

 

Thanks all for the input, BUT we went up to NY throught NC, VA, MD, and PA and back waaaayyy more hills up there and got better MPG's. Then the MPG's and roads from Savannah GA to Charleston SC.

This part of GA/SC is nicknamed "The Low Country" and no headwind.

I also had "less" weight going from GA to SC the other day. We had an extra 800+ lbs in the truck coming back from NY BEFORE the oil change. Now it was about 10-15 degrees hotter on the way up to SC but 80-ish coming home. Tire pressure good and a clean K&N CAI too. Still don't know what is up

 

how good are plugs and like someonelse said hows your fluids in tranny and rear diff? just something to think about when i did my last tune up i got better mpg's took me like 1/4 tank to goto inverness fl and back now 1/4 tank takes me to orlando and back.... and btw hip you got pics of that ebay intake? shoot em at the "my cai" thread pls.....