[pjv911]

Report back with your results. It helps feed the information available here on the forum. If your problem gets resolved it will be the 3rd time I have seen this on the 3.2 engine.
For what its worth the leaner mixture causes higher cumbustion temps which makes more resistance at the plugs firing tip.
Timing affects this too. If you have a modded chip your timing is likely a few degrees further advanced at 5500 rpm. This too raises combustion pressures causing the term" spark blowout" .
It doest happen to all of them but it is a common syndrome with that ignition system.

Kurt Williams