TheWhiteBeast

Makes me wonder if the gaps on all the motors are off...

Ecofx86

Isn't the gap still in spec at .035?

troutspinner

Just to add to the group.

I replaced my plugs with SP-534 gapped at .030 today on my 2011 Eco. I have 29k on the truck and the original plugs were all set around .040.

The reason I searched for this thread and thus replaced my plugs was because my T4 tune was stuttering/surging at higher RPM's as well as the idle was rough, even when running stock.

The truck now idles much smoother and general running around feels like a new smooth engine. I then put my T4 tune back on and Wow! what a difference. This is how it was meant to be, responsive and power through all RPM's.

The difference in gaps throughout this thread is perplexing to me. How can Ford not be consistent on such an important and easily controllable part?

Further, I have to say that this was probably the easiest vehicle I have ever changed plugs on. There are a couple of nuances which you will easily figure out, or you can search youtube for instructions but I did not have to become a contortionist or have special tools to perform this task.

Thank you to all who contributed to this post, my Eco with a T4 tune is a beast.

Lost In Sync

Time for Ford to step up and find out who is responsible for the original gap at the factory. Or factories. That doesn't look right! Factorys? No that's wrong. Factories. Yeah that's it.

SkiSmuggs

Poor running on mis-gapped plugs with the stock tune is exacerbated by the installation of any performance or tow tune. Always check the plugs prior to tune installation. It is not the fault of the tune but the fault of the plugs. The 2011 and 2012 models should always be suspect as the factory plug specs were reduced for the 2013 model and those specs should be used on the 11-12 models as well. To make matters worse, lack of quality control at the factory resulted in a high percentage of trucks outside even the misguided original specs.

martymcflyjr85

Just replaced my plugs with sp534's, all gapped at 0.031". The original plugs were gapped from 0.042"-0.045". I never had any problems with them, but glad i got them changed out. Took about an hour and half to do all 6.

Only one hiccup, I tried to move the PCV tube that runs over top of the front driverside plug, and broke the plastic nipple that comes off the intake... haha, but I JB Plastic Welded it back on, and am good too go! I will replace it someday, anyone know what that part number would be??

I will post back and let everyone know if I notice any difference, I image I will as those gaps were way out there!

UPDATE: mileage is now 19.4 MPG (was previously around 16ish)! That's cruising at 70 MPH IN 4X4! Wish I had done this earlier!! Thanks everyone for all the info!!

steelerfan7p

Also replaced mine with the SP534's on saturday. 2011 ecoboost has 83,000 miles. The plugs that came out were all about .035, and the new ones were at .025. Interestingly, the box says the gap is NOT adjustable. I didn't see that mentioned anywhere else in this thread, although i may have overlooked it. So, following the manufacturers instructions, i did not adjust them. There is no difference i can tell on how the truck runs.

brucesears

Gap should be close to .030., a little narrower if you are tuned. I run mine at .026 with my SSI tunes--runs great.

DirtMcgirt

Just did my plugs last night. I started to have hiccups/misfires at high rpm. Although I only took it for a short drive after the issue seems to be solved. Some advice, my coil clips were very brittle, pull back the red tab and press down on the stepped area on the top of the clip and gently pull the clips back (they are tight so you have to wiggle a bit). Also on the spark plug that's closest to the firewall on the drivers side there is a different clip that has to be removed. Press up on the bottom of the clip and gently pull this clip off. Also the dealership recommended replacing the spark plug boots also $3 ea. they were out of stock so I did not change them.

The Cosworth

Just read the whole thread (no excuse to post duplicate questions on page 30 people, haha). Only question I have is I have never gapped iridium plugs before. I know they are brittle and I expect to have to gap them. Any tips on gapping them?

I am going to run .28 on a 5* 87 tune. I have what some people described around page 20 about a 'miss/shudder' that doesnt register but you can feel it.