2011-2021 Ford F150 3.5L NGK 6509 Iridium IX Spark Plugs (Set of 6) LTR6IX-11

2011-2021 F150 3.5L NGK 6509 Iridium IX Spark Plugs

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Part#:

LTR6IX-11-GRP

17 Review(s) Write a Review

15 Customer Q&A(s)

On sale: $52.00 ~~$69.99~~

Retail Price: $69.99

Your Savings: $17.99 (26%)

0 in stock: Ships From Manufacturer. Average Time To Ship Is 5-7 Business Days

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Product Features
17 Customer Review(s)
15 Q&A(s)
Product Videos

Highlights:

Help alleviate spark blowout and rough idle
Excellent for both tuned and stock trucks
Features iridium tip less prone to spark blowout
Less fouling and wear than copper plugs
Factory heat range for custom tuned trucks and light mods
Full set of six spark plugs
Gap for tuned trucks: .028-.030"
Gap for stock trucks: .030-.032"

Improved Spark with Higher Corrosion and Fouling Resistance

Maximizing the performance of your truck's non-turbo 3.5L V6 engine means you'll need spark plugs that are up to the job. NGK is one of the top names in the aftermarket spark plug world and their Iridium IX series are some of the best-performing and most reliable spark plugs on the market. Each of these plugs are built to last, resisting corrosion all while delivering a clean, powerful spark for your truck's engine. The NGK Iridium IX spark plugs are an excellent choice for replacing OEM spark plugs and getting improve performance for your 2011 to 2017 F150 with a factory heat range.

High-Quality Iridium Tip and Corrosion-Resistant Design

The NGK Iridium IX spark plugs are named after their .6 mm laser-welded iridium tip that delivers a powerful arc while being highly resistant to corrosion and fouling. The insulator and electrode feature Trivalent metal plating that offers up vastly improved anti-seizure and anti-corrosion properties than traditional spark plugs. These plugs have a tapered electrode that reduces quenching while making regapping extremely simple.

Vehicle FItment:

2011-2021 Ford F150 3.7L/3.5L V6

Spark Plug Specifications:

Thread Diameter 14mm
Thread Pitch 1.25mm
Seat Type Tapered
Reach 25mm (1")
Hex Size 5/8" (16mm)
Terminal Type Solid
Overall Height ISO
Gap .043" (1.1mm)
Heat Range: 6
Wrench Diameter: 5/8"

Write a Review

2011 F-150

My truck was missing under high acceleration, and it was getting terrible fuel economy. I changed the spark plugs, and no more missing and fuel economy is back up.

Did you find this helpful? 27 of 28 Found Helpful

Reviewed by: Lee from Idaho on 3/14/2014

2011 Ford F150 Ecoboost

I started having shuttering a few months ago like it was skipping every time I would take off. I ordered these plugs in leu of the factory plugs and boy did she wake up! Can feel the power back no more skipping! Also my old plugs were gapped around .42ish and with my tuned and everything else I've done I followed Stage 3 recommendations using .30 and that's all it took! I recommend these to all Ecoboost owners out there! Also if you haven't replaced your plugs for the first time yet be prepared to buy some coil boots I found them at Oreileys for 30 dollars a boot.

Did you find this helpful? 15 of 17 Found Helpful

Reviewed by: Preston from Atlanta, Georgia on 2/4/2015

2013 F150 XLT 4X4 EcoBoost

Great product and Stage 3 has great customer service...I have the bug to modify my truck now and this company is my Go To for all my aftermarket needs.

Did you find this helpful? 6 of 6 Found Helpful

Reviewed by: (Verified Buyer) Robert Driben from El Paso, TX on 11/2/2014

2011 F150 FX4 Ecoboost

The order arrived on time, installed with a new set of Motorcraft coils. I gapped the plugs to .32, before I installed plugs and new coils I had a ruffidle (miss fire) and was getting 16.2 MPG after plugs and new coils I'm have no miss fire and get 17.7 city and 19 to 20 HWY trips 1 hour or less. Very happy with improvement. Please note oil is at 63 percent will be changing tomorrow and new air filter. However this was a great improvement. Looking to do O2 Spenser's next with cold air intake and exhaust. Oh by the way truck has 113000 on it and I burn supper gas (Shell) in it.

Did you find this helpful? 6 of 7 Found Helpful

Reviewed by: James from Texas on 7/22/2016

2011 Ford F150

Great product. Took care of my hesitation problem

Did you find this helpful? 5 of 5 Found Helpful

Reviewed by: Larry from Michigan on 3/28/2015

'17 3.5 Ecoboost

If you have a Roush stage 2 performance pack with the tune, roush recommends .32-.35, even with the NGK iridiums. I called them and asked them over the phone.

Did you find this helpful? 5 of 5 Found Helpful

Reviewed by: (Verified Buyer) Nicholas Cox from Texas on 9/5/2018

2014 Ford F-150 Platnum

Seem to help with turbo lag in my 3.5L ecoboost. Fast shipping

Did you find this helpful? 5 of 6 Found Helpful

Reviewed by: Marcus from Memphis, TN on 7/26/2015

12, Ford F-150 ecoboost

Ran these in multiple ecoboost trucks that my family has and they are hands down way better than motorcraft plugs, only able to get 15-25k on motor craft plugs and economy is down, has the shudder and idles rough again, switched to these NGKs and got 35k on one of the sets and still running awesome like when I put them in.

Did you find this helpful? 4 of 4 Found Helpful

Reviewed by: Brian from North Dakota on 5/17/2016

2013 f150ecoboost

Easy install, installed at 55k miles factory plugs had gaps ranging from .035 to .039. gapped new plugs to .030 with tune and truck runs smoother even without tune. Definitely recommend changing plugs!! Great plugs even with tune and lot extra add ons

Did you find this helpful? 3 of 3 Found Helpful

Reviewed by: Daniel from Illinois on 2/1/2017

2014 F150 3.5 Ecoboost

Great Spark plugs! I replaced my stock plugs at 120k with an exhaust and a tuner on my truck. The stock plugs became so bad the truck would start to miss if it went over 1800rpm. I gapped the new NGK plugs to 0.30 with an easy install and the truck runs better than it ever did before.

Did you find this helpful? 3 of 4 Found Helpful

Reviewed by: Chris from Pennsylvania on 4/24/2019

Gift

Thirst were a gift for my son. He loved them. Installed them right away and easily and was extremely happy with them.

Did you find this helpful? 2 of 2 Found Helpful

Reviewed by: Janet Martin from Matthews on 12/19/2017

14 F-150 3.5 EcoBoost

Plugs seem well made and the gap spacing was consistent. I gaped them down to .028 as suggested by my tuner. I'm not sure about using anti-seize with these, as I've heard NGK's don't need them, but my mechanic was adamant on that you had to use it since the motor has an aluminum head. Beware... your stock plugs will probably be very hard to get out. I had one that the ceramic cracked of while trying to remove it which is why I let this be my mechanics headache.

Did you find this helpful? 2 of 2 Found Helpful

Reviewed by: XRI-Boost from MO on 7/27/2018

F150 ecoboost

These are the best plugs, I run the same type in my race car

Did you find this helpful? 1 of 1 Found Helpful

Reviewed by: Douglas from Windermere on 8/29/2018

16 f150 3.5 eco

Easy to install. Regained the 2mpgs i had lost from bad plugs. Good product so far

Did you find this helpful? 1 of 1 Found Helpful

Reviewed by: (Verified Buyer) James from Newnan on 11/11/2017

2013 f150 fx2 ecoboost

i put them on the same day i received and damn a really big differnce i got more gas mileage and a full tank last alot longer now then before and not to forget power shit it puts out alot you can hear the supercharger whine louder sounds amazing i would definitely buy more items

Did you find this helpful? 1 of 2 Found Helpful

Reviewed by: rick arispe from Harlingen on 12/13/2018

2011 f150 ecoboost

spark plugs lasted less than 500 miles and went out. Gapped at .030 waste of money!

Did you find this helpful? 1 of 7 Found Helpful

Reviewed by: garrett from new braunfels on 10/17/2017

2013 f150 3.5L

Stick to OEM Motorcraft 580 spark plugs. You'll likely have issues if not after 10k miles

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Reviewed by: Boogle from Seattle on 2/14/2024

I have a 2014 ford f150 eco boost running bigger BD diesel turbos. Turbo smart blow off valve, BD diesel ported headers, full 3 inch catted down pipes all the way back, bigger intercooler, radiator, and a 5 start tune for 83-91 with the 91 running 18 pounds of boost up to 24 pounds I have seen basically full upgrades minus going e85 it seem with stock plugs I have 1 go bad around 25,000 miles would this help me get more life out of the plugs switch to theses gapped down to .030 plus run cooler

Asked by: Eastwood - 1/28/2026

You could probably see some benefits to going with a colder plug set like the Ford Performance M-12405-35T, but driving style and gas quality play a big part in plug life on tuned/modded trucks.