I researched where several people prefer NGK plugs to Champion.
Anyone with the Firepower ignition system on a 4.0l, what plug did you use? Same heat range as stock? Cooler? Hotter? Part#?
98 TJ Sport: 2" Skyjacker spacers w/Rubicon coils, Rancho RSX shocks, 33-12.50 BFG MT on 15X8 Mickey Thompson Classic Locks, Borla header, Flowmaster Mufler, Pioneer sound W/12" RF P3 sub and MTX amp
06 Nissan Frontier NISMO CC 4X4: 2.5" lift with Rancho RS9000X shocks, 285/75-16 BFG MT KM2s, Calmini winch bumper w/Warn 9.5cti, Alpine sound
Mdawg's 98TJ @ Cardomain