Well, got the car on the rollers the other day, got everything just straightened out a bit, tuned the fans, and didn't do a whole lot other than that. She's stock other than a cat-back, and averaged about 14 MPG in the city. Ever since we threw the new program at her, she nose dived to about 10 MPG. Someone had mentioned that the PCM in these things have to "re-teach" themselves, and that it should get better and better.
Any truth behind this?