About a month ago I bought a 1994 Honda civic, when I got it, the odometer displayed 114,967. During the month that I have owned it the odometer has reached 115,250. Today I was driving it and noticed that the 1 to the far left was slowly rolling up into a 2. So now it reads 215,254. Does this mean the odometer is broken, or did the previous owner tamper with the unit? Please help.