He is known to be incorruptible and the lobbyists don't even bother to go to him. They know he will follow the Constitution and not what they tell him.
Now see that is the story I heard 15 years ago about the "Dr. No" nickname. The story I was told back then that I have always assumed was true is Ron was given that nickname by lobbyists.
I think somewhere along the line one of his opponents may have distorted it to make it sound like Ron is more of a cog in the party wheel and doesn't "get along" with his fellow House members. It wouldn't be the first time his opponents have taken something good about Ron and distorted or manipulated it to seem bad.
I tend to believe the story I heard years ago, long before Dr. Ron became Ron Paul a legendary icon in American history.