I'll try to keep this brief...my dad has been taking care of a 2007 Mercury Grand Marquis for my grandfather, who is now 97 and living in assisted living. For numerous reasons, they've now decided that the car is to be sold. When my dad took over driving the car in 2013, it was showing about 24,000 miles on the electronic odometer, and he had the car inspected (They live in NY).
When he took the car to get it appraised at one of those "we buy your car" places, they pulled the Autofax and it showed an issue with the odometer. My grandfather bought the car used in 2007- it has about 10,000 miles on it and was a previous rental car. Subsequent NY state inspections had mileage reports of 14,000 miles, then 17,000 miles in 2009.
In 2010, for whatever reason, the mileage jumped to 32,000. While grandpa was still relatively mobile and active at that point, I find it hard to believe he put 15,000 miles on a car in a single year. Inspections for 2011 and 2012 showed mileages of 35,000 and 39,000, respectively.
And, of course, now the odometer is showing about 33,000 miles (dad's put about 8,000 miles on the car since he got it). Which leaves us with two questions:
1) How did the mileage seemingly jump 15k in one year, when all other years were 3,000 to 4,000 mile increases?
2) How did the mileage "roll back" 14,000 miles between the time when grandpa got the car inspected in 2012 and when dad started driving it in 2013? The car has never been in a wreck.
Unfortunately, adding to the mystery is the fact that the dealership where grandpa bought the car is no longer in business. They are simple a repair shop now, and not even a Ford authorized one, just an independent. Dad asked there and they have no records. He also can't find records of where the car was inspected, and grandpa had a stroke and can't communicate anymore.