Check the voltage between the resistor and the ignition unit, and keep an eye on it, does it stay consistant or does it fall off when it starts to crap out?

Maybe for some reason after a time the voltage to the unit falls off. At some point the electronic ignition cannot effectively keep the plugs clean.

Allen Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first. Life was a little easier when I was just a wrench.