Review on 🔥 NGK 4291 V-Power Spark Plug - ZFR6F-11, 4 Pack: Top-Quality Ignition Upgrade for Optimal Engine Performance by Nick Ward

Installed on 2004 WJ Jeep Grand Cherokee No HO 4.7L. Direct replacement for factory Mopar SPRC12MCC4 and Champion #439 forks. The gap in this application is 0.040 inch. Plenty of cars that recommend a copper connector are good for upgrading to platinum, iridium, ruthenium or any other new magic metal and crazy connector design claiming massive performance increases and +3. -5 mpg. For some reason the 4.7 gets angry and causes pre-ignition at certain engine temperatures and RPM with unicorn dust spark plugs. Stick to copper candles or factory nickel-plated copper. Mother Mopar says swap at 30k, I'm used to 15k Of course they're still ok, but at 15k I see visible wear and melting of the electrodes on the NGK show champion melts at 10k You say that's wrong?! In general I agree. But 4.7 is a weird and wonderful beast, and eating forks like your Uncle Chet eats beer nuts is pretty typical. Even though I love 4.7, it's definitely a curse. I even know it's over 15k but copper forks are cheap I don't mind working so what could be wrong with that?! My side effects are fast starts, smooth idle, peak power and consistent mileage. Get some of this.