Faith and Reason

I was wondering if anybody could shed light on what I regard as a puzzle. Do those who have faith have to arbitrarily stop reasoning beyond a certain point? In order to interpret what it is one has faith in, reason must be used but that same facility will also tell you that your faith is not based on sound evidence (by definition). So how is that delicate equilibrium maintained? Or is the situation, on closer inspection, no different to how things are for an agnostic like me?Some might want to argue that one needs faith in order to accept Reason without proof and that you can't prove the validity of Reason itself without circularity. However, rejection of Reason is self refuting, so I don't think one needs faith, in the ordinary sense of the word, to accept Reason on a rational basis without proof.
Of course, if your reason leads you to a position which you regard as compatible with your faith position there will be no risk of cognitive dissonance at the interface between faith and reason. But if, as I have, you come to the conclusion that there is no rational basis for belief in any of the religious truth claims, yet you still have faith, how does that work?