[airair]

I would expect that this is an issue of club face control, that you are not consistent getting the face squared up in your swing. It may be open at impact much of the time, causing the weak fade/slice. Occasionally, when you get the face squared, the ball goes straight. Maybe working on clubface control would eliminate the inconsistency.

The problem is that a straight clubface hitting the ball on this out-to-in swing path dosen't make it go straight, but results in a pull. So I guess the clubface has to be a little open, but not so much that it results in a slice? Maybe it's the D-plane that makes it go straight occationally ?(Which I don't know anything about).