What causes the engine on a Ford to shudder after the O2 sensor bank one was replaced at the advise of a Ford dealer who said it would repair the problem?

Check all the basics, plug wires, codes(check engine light), Vacuum tubing, etc...could be alot of things, but probably not in the O2 system...also, your local parts store should be able to loan a tester for the Check engine codes...:)