Mazda MX-5: NGK Laser Iridium Spark Plugs Replacement ILTR6A13G

Today’s project was to replace the original FoMoCo spark plugs at  52,800 miles to new NGK Laser Iridium model: ILTR6A13G #3789.

There was absolutely nothing wrong with the old spark plugs. The car ran fine. There was no missfire. No rough idle. No issues with the fuel mileage. I didn’t have to do it. But I changed them because the price was right. I managed to score a set of four through eBay for $27 dollars shipped (after a $10 discount code). Which made it a good deal, and I’m happy I got that taken care of.

The old plugs look to be in fantastic shape. Although I did have a bit of a hassle removing two of the four plus, specifically those closest to the firewall of the car, the second from last spark plug was especially noisy when coming out making a very faint clicking sound as I turned the wrench, so I gently rocked it back and forth tightening and loosening it in the process. When the plug came out there wasn’t but a spec of aluminum maybe one millimeter in size on the thread that I assume was causing this noise. I’m glad I got them done now closer to 50k miles and not at 60k or 75k like is recommended because surely the spark plugs would have been tougher to get out with use.

Restarted the car after the install and it purr’s like a kitten. Not sure if it’s any quieter than it was with the old plugs, but I’m looking forward to finding out if it improves my gas mileage. I have been getting 33 to 34mpg’s consistently on recent road trips.

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I’d say this is a very quick 10 to 20 minute job with all the right tools, there’s only an 8mm and a 16mm socket required for the coils and plugs, and a 12mm socket for the brace to gain access to the very last plug along the firewall. Glad that this piece of maintenance is completed. Going to have a road trip to Lime Rock in a few weeks to test the gas mileage, I do expect to get there and back on one tank.