Quote Originally Posted by Phantom View Post
With heavier rims and city driving that can badly hurt MPGs others might not get as bad of MPGs but they are doing a different drive than you. With heavier rims increasing speed is harder but maintaining speed is easy so in stop and go traffic they will hurt the most.

You said that every 3mi trip the mpgs go down, if you are doing 3mi trips the car will not fully heat up and will use more fuel.
This didn't make any sense. There's no excuse for a healthy NA 3800 to make 13mpg, ever. Something is broken.