Spark plug NGK or BRISK

The car started to misfire at boost so I swapped plugs to NGK PFR6H-10 and everything is good now.

Don't use Bosch sparksticks.

I use iridium’s NGK haven’t had any issues.

Just replaced my previously purchased NGK Iridium from Rockauto.com After 100k miles the looked like I put them in yesterday.

NGK Laser Iridium is the Honda spec and what I buy and have had no issues for 5x 105k intervals.

I read that NGK plugs already have a coating on them, so I didn't apply any when I fitted new NGK BKR6EQUP plugs. Torqued them to 25Nm.

The old ones (also NGK) came out easily and I used a bit of tubing to hold the plug as I installed it into the thread, making sure it was threaded on straight before switching to a ratchet and torque wrench to screw down and tighten.

Every one of my internal combustion engines (3 cars, 2 motorcycles, zero turn mower, has NGK plugs.

Been using the cheaper Brisk brand and never had an issue for 20k miles.

It's hard to go wrong with NGK spark plugs on Japanese vehicles. That's what I've always done with great luck.

We bought a 2015 Mazda CX-5 that has 155K miles on it. Plugs never changed by prior owner. It was giving us **26 MPG**. The engine was rough at idle. So I read and read about Spark Plugs and purchased NGK LKAR7AHX-S Spark Plug NGK Ruthenium HX Spark Plug that this is better then the OEM ILKAR7L11. So we installed the HX, we noticed the engine smoother but the MPG dropped down to **24 MPG consistently.

I replaced the spark plugs with NGK Iridium IX factory gapped to .044". Everything went smoothly, reinstalled coils, air box, battery, connected MAF, and started the car. Now it is shaking, smoke coming out the exhaust, and blinking check engine light.