have never heard of cumulative testing....but maybe i have been doing it wrong for years! i remove both plugs on a cold engine, give it 5 or 6 good fast pulls, release pressure and go to the next cyl.
Thanks for the offer LeeRoy...may have to take you up on that after your hunt...today I tested spark with a tester and got good blue spark jumping 3/8 gap....I also re-did the compression check and had 95 on top 100 on bottom...i replaced the suspect plug with a new one and she started right up but still has the mis-fire / back fire especially when reducing the throttle from higher to lower speed...I'm not sure where to go from here and i'm open to all suggestions...thanks!
