rvtrc211v

My 2013 5.0 also has a rough Idle and a weird knocking noise. the knock isn't constant only happens every now and then. I checked my plug gap and the first one I pulled was at .50 and the other 2 I checked were the same. I looked at the manual for the 2013 f150 and the plug gap spec says .49-.53. Why would Ford change the spec from 2011- 2013? I'm wondering if I should pull the autolite plugs and run NGKs? Did your truck improve? I'm sure you have some millage on them now and you know for sure if it worked or not.

ClaySlayer

I regapped mine ~6-7 months & ~10,000mi ago (truck has 49,000 on it now) and still running smoother...it didn't run smooth as a baby's butt after the regap but definitely smoother than it was. 2 were 0.047 and the other 6 were .050-.055 so I set all 8 to .045. I swear it even runs better under load at low rpm too like climbing a hill or towing my boat.

yotehunter

I set the gap on mine at .045 also and got the same results. Truck pulls much better in 6th gear at 1000rpms on up.

rvtrc211v

Thanks for the feed back. Did the knock at idle go away?

Daimyo68

imo, while there are several types of "gappers" out there, the wire gappers are the best.

rtpjunior

iTrader: (4)

After I re-gapped mine, I still was getting knock occasionally. It was most prevalent when I would try to lightly accelerate from a slow cruising speed ( like 25 - 30). Engine would knock for less than a second, but I could definitely hear it. I replaced the plugs last week and gapped them at .043. So far so good.

rvtrc211v

I gapped the plugs to .45 and my MPG went from 16 to 17 and that was with 1000+ in the box. The idle is a lot smoother and I cant hear the knock anymore. Thanks for your help guys. ill keep you all updated on new developments.

svt2205

I recently replaced the plugs in my 11 with 93K on the clock. The plugs that came out had .052 to .053 gaps. Really not bad considering the number of miles. I installed Motorcraft SP-519, which are gapped at roughly .051 from the factory in Japan.


What I find interesting is the 11 owners guide lists .041 - .047 and my factory service manual (downloaded off the motorcraftservice.com site) lists this as .049 -.053. It wasn't until I noticed this thread that I looked and found the difference between these two Ford documents, but now I'm wondering which one is correct. My 11 runs just as it did before changing the plugs out. Too cold here in NH to have any knocking but each summer I do experience a light knock. Nothing I ever worried about. I doubt that I will pull the plugs and regap.


Now, how do we obtain the correct spec information?

026TB4U

Do you have access to the service manual for the '13s? Curious what it says.


I downloaded the owners manuals for the '11 and '13 and they are definitely different as mentioned here.

Ned Fletcher

I looked it up in mine, and it agrees with what the guy at the top of page 2 said, .49-.53. I have a pretty rough idle occasionally (truck feels like its trying to die) and I am considering going to .45, but I do not want to go outside of factory specs.