I did a tune up iver the weekend and changed my champion spark plugs to the NGK plugs and notice two of the plugs I removed, one from piston 1 and the other from #4 were barely worn down versus the other four were pretty worn down. What's the diagnosis for that?

 

Maybe the previous owner only replaced two recently?

 

Oh srry I should have elaborated a little more. I changed them about 32k miles ago. About two winters ago figured it was time to do it again. Four spark plugs electrodes where pretty worn to a point that it was close to time for a swap. Two of them hardly looked like they were worn at all. All spark plugs showed normal operation when looking at a spark plug diagnosis diagram. So is there anything to worry about....should I be concerned that two pistons are not operateing the same as the other four or are the other four the problem that they were worn down more than the other two.

 

It's because they were Champion plugs. NGK was the right choice for replacements.

 

That seems to be the answer I get from other places. Haha!