Thread: would hi-mileage/worn spark plugs cause KR at WOT/PE?

Try the new plugs only gapped and scan. Then if you want, side gap the plugs and do it again. My car did not like the AR 103's and they had the cut back electrode. Those were the only plugs out of all I tried that it did not like.

However, most say the AL plugs are only good for 10K so cutting back the electrode reduces the life even further, You're probably close when you say two oil changes worth of time.