[cj847]

At the level of detail you are working, I would wait til you had 5k miles or more on the engine. I would be concerned that your motor is "tight" causing part of your gas mileage issue. The other items that will affect gas milage:

-what is the diameter of your tires?
-does your starter turn slower when the engine is hot vs cold start? (ie engine is tight)
-do you have excessive "slippage" of your torque converter (assuming it is a non lock up?)