Denso Iridium Spark Plug, 1-pk

Great plug much too expensive

Changed plugs at about 296,000 kms, about 55,000 kms/ 3.5 years since the spark plugs were last changed, much sooner than expected. The car stalled and the engine misfired after a car wash at the Agincourt Canadian Tire car wash, at Sheppard and McCowan. The 2nd time this happened at this car wash, stalling and misfires, I checked the engine and there was water all over the engine compartment. Something had changed with the force and direction of the water sprays that clean the tires/ undercarriage. Now, I drive quickly through this part of the wash, and no longer experience the misfires. No misfires in rain or serious puddles, just this car wash, and just recently. Have been going to this car wash for decades, and still go to this car wash, but slightly paranoid now of the undercarriage spray. No surprise, since the misfires, the car experienced reduced performance, with noticeable vibration at 110-120 km/ hr. Upon changing the plugs, 1 of the 4 plugs had a noticeably deteriorated and larger gap. The other plugs were like new, so I kept those as spares. Upon changing the plugs and wires, the car can now pass at 140 km/ hr without vibration, and accelerate much smoother, with more low-end torque.

Had these installed in a 2014 Jeep. Have always used copper plugs per the manual recommendation. Canadian Tire shows these as a best choice replacement. Best plugs I have ever used in my vehicle. Fast starts, great power and acceleration. And so far, they have given amazingly good fuel economy.

The car was feeling a bit sluggish. It was about 74,000 kms/ 6 years since the ignition wires were last changed, and 54,000 kms/ 4.5 years since the spark plugs were last changed, and about 80,000 kms/ 7 years since the battery and alternator were last replaced. The car's at about 241,000 kms, and I'd like to hit 300,000, so I decided to splurge on these premium spark plugs. Took the plugs out of the box, and inspected them before leaving the parts counter, just to make sure. Apparently, there is no need to gap these plugs, so it was a straightforward install, but I forgot to apply anti-seize to the threads. Also replaced the ignition wires at the same time. Scrubbed the battery terminals with a steel wire brush, and applied dielectric grease everywhere, while I was at it. Looking at the old AC Delco spark plugs, some definitely had wider gaps than others, and some of the old ignition wires had signs of arcing. The ignition coils have signs of serious pitting, but no misfires, so won't change those just yet. It's been about 1,000 kms since installation, and the engine runs smoooth, and there seems to be more pep and nuance when I press the accelerator. Hard to say if these Denso Iridium spark plugs perform better than new AC Delco spark plugs, but I'm pretty sure they don't perform worse. Hopefully, I can get another year out of this battery, and another 60,000 kms out of this car.