A while back after changing my tstat noticed a couple of wires rubbing against the valve cover gasket,turned out to be the knock sensor wires which i put a wire loom over themto protect from heat exposure,today noticed a green and black wire almost in the same area rubbing on the valve cover gasket but also screwed into it as a ground,it was a pita to place the wire loom over it,hopes this helps someone from future headaches.