Re: 99 Navigator Plugs and Coils
First off I've found oem to usually be the best as far as ignition components. Coil on plugs especially. As far as plugs go I'm a mustang enthusiast and I mod everything I own,and I do all my own work.
I've been using NGK plugs,the iridium ones because I've got a dohc 4.6 in my mustang,and I want to limit plug changes.
My 5.0 fox needed plugs so I couldn't find the iridiums and all Canadian tire had were these e3 plugs. Now I don't believe the hype when it comes to super duper plugs but I gotta say those e3 plugs made a noticeable difference in pep. And I had removed iridium plugs to put in the e3 plugs,so I'm sold on them and won't buy anything but now.
I always thought a spark was a spark right,and I didn't buy into gimmick plugs. I bought iridiums because they lasted longer between changes.
The e3 plugs re also supposed to be a long life plug,I don't know yet about lifespan but I've used them now in my 88 hatch 5.0,my father in laws f150 with a 5.0,my dohc 4v,my girls windstar and I had them in my hemi and in every vehicle the engine ran better with more noticeable pep.
My girl said she's getting better mileage but I found a plug wire that was shot,so I'm not prepared to give that to the plugs.
As far as mileage in the mustangs I don't keep track. I drive them hard and measure those cars in smiles per gallon.