mustangguy289

How can these two part #s be interchangable? The 5325 has a washer/gasket seal. The 5364 has a tapered seal.

Did our trucks come with tapered plug or a plug with a washer?

CoreyMS

Its all changed now. Now autolite says the 5364 is for the 3.7, and a new xp 5363 is for stock heat range eco. You can't even find that plug. The specs on the two of them are the same.

I switched back motorcrafts until I find more info.

mustangguy289

I am so damn confused lol.

Nobody even list a plug for the 2011 f150 ECO.

mustangguy289

So which plug should I get for a stock 2011 Ecoboost F150?

CoreyMS

Motorcraft for now. I think its the sp-528. Or go to the dealer, and tell the parts department you need plugs for it, I'm sure they have some.

deejayarecue

Just replaced the plugs in my 2012 FX4 SuperCrew Eco with factory Motorcraft SP-528's gapped to .30. The plugs I pulled were all around .40. Truck has 26k miles.

So far it's definitely running better. The idle still isn't superrrrr smooth, but better. Throttle response seems more accurate. My gas milage is back into the 18-20mpg range (highway) with my BF Goodrich All-Terrain T/A's in LT275/65r18 (same size as stock but heavier) on 91oct.

I'll report back if anything changes, but so far so good on day 1.

K-Dubb

Is it recommended to check and regap even if you aren't having issues an currently stock?

Joewee3.5

Just because you're not having issues doesn't mean your truck wouldn't run better with proper gap. Doesn't hurt to check.

8WOOD

Hey, I'm a nub to the forum. I have a totally stock 2012 FX4 ecoboost with 5000 miles. I just regaped the plugs to .030. They were all within "spec" .032-.034 as the manual says. I didn't have any issues except around 50-55 in sixth gear pulling up hill with a tiny bit of boost, a very very slight shudder was noted. It didn't really bother me as most boosted systems have slight shudders at certain lugging rpms. I read this thread and decided, I'd change the gap. Guess what no more shudder! Other than that nothing else has changed. I still see 10.2-10.5 afr, and ~12psi tapering to ~9psi. Anyways, thought I'd share that info for those who are having the "shudder problem."

On a minor note, when removing the engine cover the maf looking sensor in top of the intake manifold has only one bolt, but a spot for another one. Anyone else missing this a bolt?

Lost In Sync

It's not missing according to several other posts about the same thing. It's made that way.