My family and I recently went on a week-long trips to from Minnesota to the Black Hills of South Dakota and back. It was a 2000 mile round trip. The tank before I left I got the best average I ever had @ 58.5 mpg with a little effort. The roads between MN and SD are 80 mph roads and I pushed around 83 to 85mph and while we were in SD we were constantly going up and down the enormous hills all day. In addition to that we'd be parked in waiting lines with the AC on for long durations so that my battery would be down to 2 purple bars. Then we'd take off and head down hill in B mode until the batter was 100% full and it would switch to ICE braking. During the trip the best MPG I got was 43 and the worst I got was 38.5 while doing 85mph. Now that I'm home i'm struggling to hit 50 mpg. Do you think I did something to my battery by cycling them so rapidly? I've got 140k on my car. Thanks!
There are 140,000 reasons over 10 years why your gas mileage might be going down.....and your battery getting weak. It probably wasn't the best idea to drive it at 80 or more either. Are you sure that you have reset the MPG computer so that you are not looking at a long term average ?? Have you checked the oil any time during or after this trip ? High speeds on an old engine tends to use more oil.
