Since you are using a canned tune, you must ask the Magic 8 Ball ...!
Most people run plugs gapped at 0.030 when tuned. If you did not put in new plugs, you may have the old SP528 spec plugs, which are prone to cracked insulators. So might as well put in new SP534 plugs, check to see if gapped at 0.030 (they come very near that from factory, or so I hear). no point in pulling out old plugs and putting them back in. Once tuned, the lifecycle of plugs gets shortened.
If you do pull the plugs, please post pics!!!