I had the Honda recommended software upgrade done on the car in July 2010 and have taken it back twice to two different Honda dealers more than once. The gas mileage has dropped from 44 to 40 consistently for the same route and driving conditions on my daily commute. Worst still the car’s power has suffered as the battery does not kick in as often so it struggles going up a hill. The battery is in charge mode more quickly at roughly 50% life so it is not available to boost the power, prior it would not stsrt recharging until much lower like 20% left. In fact I have had to turn around on hills that it could manuever before as it would not go up hill after the upgrade. I have spoken to several other drivers of the same model that say they have the same problem. The software upgrade was to lengthen the life of the battery pack not kill the power and MPG of the car. Any recommendtaions on how to fix since Honda is of no assistance?
The above is a quote similar to a problem I have.
Did you perhaps notice the “same dramatic drop” because you are the same person as the original poster?