The before and after on a 2012 F-150 I just did is wild

Picked up a job last week on a 2012 F-150, guy said it was running rough and eating gas. Before picture: spark plugs were so crusted over they looked like they'd been sitting in a swamp for 3 years. After I swapped all 8 plugs and did a coil pack on cylinder 5 that was cracked, truck runs smooth as hell now. Owner said he's been dealing with a rough idle for like 6 months and just thought it was getting old. I told him straight up, that's neglect not age. Has anyone else seen that kind of jump in performance just from basic tune up parts? I swear people forget plugs are a thing.

2 comments

2 Comments

the_fiona4d ago

Yeah, I see this all the time with Fords. That generation of 3v Triton is real sensitive to bad plugs. I did a set on a buddy's '11 last year and it was the same story, rough idle and crap mileage for months. People just assume it's normal wear and tear when really it's a $40 fix with basic tools. If that truck had misfire codes stored I bet the coil on cylinder 5 was on its way out too.

miller.avery2d agoTop Commenter

Coil issues always show up right after you fix the plugs... happened to me too.