I will take a guess that having a loss of MPG, or not, may be related to the mapping the car had before the upgrade. May need to be more number specific, and stick to something that is more comparable such as only highway MPG. Average means nothing as everyone has different driving patterns.
Thinking out loud something like:
Was able to break 40 MPG highway before and after
Was able to break 40 MPG highway before but not after
Was never able to break 40 MPG before or after
May also want to ask when was the car built (when the DME was originally programmed).
Last edited by KeithS; 08-13-2012 at 06:32 AM.