Mine is off as well...ran next to a friend in his truck and he said I´m 5mph slower....radar gun they have on the highway here says 10 slower!!!! If I´m at 65 it reads 55.....dealer said they make them that way to give you the feeling you are going faster than you are???????? I personally would rather justy know how fast I´m going......the dealer also told me that the faster I go the more it will be off ???..makes no sense to me...but he also said there was nothing he could do about it