My 2006 Specialized hybrid started to freewheel this A.M. just as I was leaving the house. I noticed it the last time I rode it that it was acting like it would slip a cog once in a while, the bike has a few miles on it, maybe a 1000 but not abused. I tried different gear combos but it still would do this. Any ideas appreciated. Gonna take it to my dealer and have then take a look but would like have a few clues before I do.