What plugs did you put in? IF you purchased Iridium or Platinum and tried to gap them, you might have bent the nipple sticking up.

If you got copper, gap them at 50 and good to go. I've never gone larger then a 55 gap on mine, others can comment on if 60 is to much.

Did you replace the wires? If not where they ok? seated good on the new plugs? create a short when pulling them off and reusing them?