Because you say the bow shoots a couple good arrows and then starts shooting right again I would think this has more to do with a draw weight that might be alittle heavy and form problem. A bow even when not set-up right should have the same problem consistently ie. arrows porposing, fishtailing etc. When I hear about a bow that changes after a couple shots I always think that the shooter is doing something different. I have seen a bow with a bad cam bearing that sometimes would cause the cam hang-up enough that it threw the timing out, took forever to figure that one out.