I own a 98 F-150 4x4 and recently installed the DG508 COPs. Can someone tell which spark plug has proven high performance, long life and better mpg in the 5.4 L - there are so many to choose from: Nology, ZEX, Bosch, Sonic conversion...........?

 

I can only state 'long life' for my Bosch + 4's.... I know I'll get hammered for running them, as I'm just about the only one on here that has had any success with them! I've got just a little over 100,000 miles on mine and no misses, no drop in mpg since putting them in... I've pulled #1 a couple of times over the years and it seems fine... No wear on the center electrode and it's been a nice tan color each time...

I've not had one 'launch' on me either... I'm still on my original COPS, O2 sensors, MAF, EGR....

The original MC's I pulled out at around 65,000 miles looked ok, but the gaps where way over the spec... I picked the +4's before finding this site because they don't need to be gapped ever and they get a pretty good beating here, but I like mine!

Hey jbrew... I just had to comment again on my +4's!!

Mitch

 

I ran my last set of MotorCraft Platinums for 120K before changing them. The truck ran fine, but I was scared to change them because of a plug launch after the first change. For 120k, the plugs were in amazing shape still. I'm hoping that I can run this set to 300K, not worry about it again......