Owner reviews for spark plug

I have a 3.5 ecoboost. All 6 of my Ford plugs failed because of cracks. I replaced them with AutoLite iridium XP5863. They are all still going strong after over 50k miles.\n\nThe Ford plugs failed with a cylinder misfire error code. The engine would also bog down under havy accelaration

I upgraded to NGK Iridium spark plug in my classic 500, 2 years ago. There were minor but good changes in performance.

The fuel economy increased a bit and the self starts have been better.

I have a 2018 Macan GTS 70k miles. So far this is what I’ve done….upper and lower control arms, spark plugs, pdk serviced, brakes and new tires.

Subaru forester. Mine is a 15. Comfortable, decent gas mileage, able to seat 4 with stuff in back. Kayaks fit on roof. AWD helps in rain and snow. Easy to do basic maintenance, but spark plugs SUCK.

NGK, used them for years in multiple cars. Seem to last longer, but I have no proof.

New NGK plugs this summer and she\u2019s still purring away (and snarling when I drop the hammer). Honestly its one of the best motors ever to come from Honda and I\u2019ve loved both of mine.

I used NGK laser iridium to replace my probably original 256k mile acdelco plugs. Noticed exactly no difference in performance.

the cheap, no name one it came with was doing the exact same thing as the new NGK one I put in (and properly gapped) to try and remedy the issue.

Cylinders 1-3 were misfiring. They couldn't get the spark plug out of cylinder 3 because the other dealership had over tightened it. They had to get a special tool to remove it. The tool BROKE because apparently it was so overtightened and mis-threaded. They finally got it out yesterday and sent the cylinder to the machine shop to get the head off. I just got word that there is a hole in the piston and the valve head is completely gone. They are saying now that it has nothing to do with the spark plug being overtightened. He asked about driving through water, and road conditions. It was a dry day. Not an issue. They said I need a new motor at this point.

I bought eight new AC/Delco from eBay. While gapping the plugs, I noticed that in two of them, the ceramic was not concentric with the body of the plug. It's difficult to measure, but it's easy to see by eye. I'd estimate the error is about 0.02 to 0.03 inches.