Spark plug NGK or AC DELCO

AC Delco/NGK.

IMHO, this is one of the times where the OEM stuff might be the best way to go, especially if your engine is otherwise stock. It's really common to see these trucks get well over 150,000 out of the original plugs and wires. They're kind of expensive but they just last so long it's worth it.

I went ahead and replaced all 4 coil packs and plugs as well as the PCV valve. Since I have to order parts, it seemed faster than checking the plugs and swapping coil packs, as well as good insurance, since the coil packs and PCV valve were (over)due for replacement anyway. It took about an hour without rushing. Took about a 30-minute test drive, highway and town, and the engine's running smoothly. Ran a scan when I got home, and no new fault codes, so I cleared them all out and the check engine light went out.

I have always used double plat or ngk laser iridium with no issues in my 2.5.

I ran stock plugs for a while and they got chewed up fast. On NGks now and even pushing 29 psi they keep the gap well.

I run the IS38 FBO and beat the crap out of my car and use stock heat-range Rutheniums.

Spark plugs. NGK 4 lyfe

NGK spark plugs are preferred in rotary engine (RE) Mazdas and Nippondenso is the only acceptable substitute that I ever found. We dealership technicians, always found it remarkable how a set of Champion or AC spark plugs could instantly cripple a rotary powered Mazda.

My 2017 Jetta SEL with LFER7BHX 9512 plugs starts/runs fine at 50076 miles, 0-100 degrees F.

The only thing I noticed when it was extremely hot and humid my car was slow in accelerating.

I've had my 2006 Audi a3 3.2 quattro dsg for 5 years now, and every year or so I will have an issue with a misfire on cylinder 6. It is always cylinder 6. I use the recommended NKG IZKR7B(7563) plugs. I often find that the cylinder 6 plug has a crack on the ceramic insulator around the electrode. On one of the plugs, half of the insulator is missing. Replacing the plug always fixes the misfire. I also noticed most recently when I removed the damaged plug, it was very hard to turn and some of the aluminum from the head has fused to the threads, leading me to believe that the cylinder is getting too hot.