I have been a customer of NGKPlug for a long time. I have tried many different Plugs. Iridium plugs were not very effective. I used it for my 2Cycle car this time, and since I change plugs more often than my 4Cycle, I can use it with confidence at this price range.
The Engine was not sputtering very well. Ignition coil was replaced at the same time. It had been about 10 years. The Engine malfunction did not improve, but I am satisfied with the dress-up effect.