Matt1377

In the scheduled maintenance section of the drivers handbook it states to change your spark plug at 100,000 miles for the first time. Is this necessary or can they be changed at a later mileage.

WXman

Well, if the truck is running fine you can do it later. But on the 5.0 it's only about a $50 job and can be done easily in the driveway with hand tools so why not treat your truck right?

Matt1377

I have the 3.5 eco boost. Does that still apply?

WXman

On the EcoBoost, I would strongly recommend changing the plugs well early of 100,000 miles because the direct injection and forced induction will foul the plugs sooner than a traditional engine. I'd do those no later than 60K intervals at the max if it was me. I have no idea how difficult the plugs are to change on that engine.

Dan M.

Ford says 100,000 on the 3.5 Eco. Has anyone with a high mileage 3.5 gone that far without a problem?

sgoodgame

I changed mine when I got the truck, at 85k or so, just a few weeks ago. The gaps were almost double the spec. Change them early. A buddy of mine changed his at 50k, and they were a fair bit out of spec already.

tribalgear

I doesn't hurt to change them at earlier mileage. More than 100k miles seems over use and I'm curious how these sparkplugs looks.

WXman

I did mine at 100K and all eight plugs looked fantastic. But then again, the Coyote and EcoBoost are two totally different animals.

FredB

I always change the plugs early. The wifes Rogue was also recommended for 100K, changed them at 60K and the gap was way out of spec, runs a lot smoother after.
I will change my truck, F-150 2.7, @ 40K, currently @ 37K

Pyzon

Changed mine (3.5 EB) at 52k and gained almost 2 mpg, Did the air filter too, so maybe that was half the increase. 45 minute job the first time, probably half that the next time.