A newbie general question about timing belts.
I often hear it said that a loose timing belt or broken tooth could cause the timing belt to slip, thus affecting the timing and causing the engine to malfunction.
But, could that account for sporadic problems? I mean, it would seem to me (having just looked at my timing belt) that if it slipped, it would be at a new position, and it would be very unlikely to slip *back*; so, I would think that the timing would be consistently screwed up from then on, and although it might slip further and get worse, it wouldn't ever get better; the timing problem wouldn't come and go sporadically.
So what's the real story? Is there more to it than my simplistic understanding?
Also, what is the effect of slipping by one notch? How much would that affect an engine's timing; how noticeable would it be?
If it matters, I'm driving a '95 VW Cabrio; but the question is a more general one.
Thanks!