I have replaced the Stems in my Standard 3 stem shower and am still having problems. I am getting leaks off the H and C stems when I divert the water to the shower. I also have a problem with the cold water knob after I turn on the cold water it continues to open all the way on its own. Any Suggestions?

First thing to try would be tightening the bonnet nuts on each stem.

First thing to try would be tightening the bonnet nuts on each stem

Yup! Sounds like a great place to start!