Hi I have a 2012 mustang gt 5.0 and have just replaced my alternator and in the process before i got started i had disconnected the positive terminal on my battery, replaced the alt and idler pulley and belt. When all was done i connected the positive cable back to the battery and since then have noticed that on my dash it says 310 miles till empty, now with a full tank it only says 198 to 204 miles till empty. I also have noticed that the gauge seems to be working right and as i drive to work approx 6 miles away it deducts that from the 310 mile reading. My question is how do i reset this if at all possible? stumped on this one.....Please Help