Absolutely! I believe in the existence of George W. Bush and have conclusive proof of it. Does that mean that I have faith in him? :-) Well...nope!

Satanists believe in God, but reserve their faith for Satan. There you go.

Lots of people believe in God, yet pay scant attention to God most of the time. Obviously, their faith is not very strong.

When faith is strong it produces results. When it isn't, not much happens. You can believe in something, yet have no faith in it at all....God included.