What makes a car have an affinity for a specific brand of plugs? Anyone know? What I've noticed is that my Ru's are happiest with NGK plugs. Not that they don't run right with other brands, but I do get the best mileage out of NGK's. On the other side of that is my wife's Ranger. It doesn't seem to car a lick what spark plugs it has, and its seen them all. Its got motorcraft plugs at the moment, but its seen Bosch, NGK, Champion, Delco, Denso and a few others. No noticable or measureable differences in performance or mileage. Any ideas?

its about heat ranges being correct. the resistance makes a differance. and the construction also determines the durability.

 

I too swear by NGK on most all japan built cars and trucks.

 

but I also have learned that cars like what came from the factory. Champion plugs are junk. but Dodges love em. they can actually set codes if the wrong plugs are used.

delco plugs in a GM

and yeah put whatever you want in a ford. They always seem to run funky.

and yeah put whatever you want in a ford. They always seem to run funky.

amen to that(i hate my ford why can't subaru build a full size truck)