Not just the plug boot, some of the plugs as well have resistors to prevent such a thing....I know for a fact that most Champion plugs can be gotten with that option.
Lemme know what kinda ped that is, and what plug yer using now, and I can find out the part # for a resistor plug in the correct heat range.
That should help a lot...they're designed that way to eliminate this exact problem in cars.
-Ree