What about the autoplunger forks? Have they bent outward so they aren't hitting the ball evenly on both sides? Is the autoplunger fork mechanism sloppy left to right on the pivot pin? (You can put washers in to reduce the slop).

If that's ok, I would check the resistance of the coil using a multimeter in the ohm position. You may just have a coil that's headed out to pasture and needs to be replaced.