John 8:1-11 is a powerful story. Unfortunately, from what i understand, it isn't in the earliest manuscripts and most scholars believe it to be a later addition.
Whilst the original gospels included made up stories by people who never knew Jesus a generation after he died, this made up story seems to have been put in at a later stage, thereby somehow making it dubious.
Personally i think it is a highly resonant passage with positive implications and deserves to be followed more than much of the so called original material.