I'm here to revive this old thread and let anyone who is thinking about doing their spark plugs, atleast on the 3.5 ecoboost, it's very easy. Nothing else to take out of the way other than the charge pipe's 1 bolt and couple of clamps, have the 6 inch swivel ext and a 3 inch ext for the back otherwise it wasn't a big deal, just did them in about 1.5 hours and that included a trip back to the auto parts store in my wife's car to exchange the 1 incorrect plug I was sold. They didn't have the NGK's and I wanted to go iridium so I went autolite iridiums. I only have 80k miles and am the 2nd owner since 60k, I wasn't sure if the plugs I pulled may have original so I figured better safe than sorry, they were only slightly gapped at around. ..40. Torrie at unleashed had recommended...28, I went around. 30... I also just did a mobil 1 oil change and filter and sync 3 upgrade! My explorer is getting all the love this month.