Ford Racing (M-12405-35T) 10-17 Flex 3.5L EcoBoost Cold Spark Plug Set

After tuning my 3.5 ecoboost and noticing a misfire on cylinders 1 and 5, I moved coils around. The misfire remained on same cylinders and I had good compression so the plugs were not performing well. I bought these due to colder heat range and closed the gap to .028" and the truck runs amazing. It runs smoother than it ever has !!

Use to replace my stock plugs at 40k after I got the 5 star tune. This helped stop the little stuttering at idle and the truck runs a lot smoother and cleaner. I got these per 5 stars recommendations as they are high performance. This was the easiest tune up I’ve never done, took me 20 minutes,10 minutes per side. Just make sure to get dielectric grease. I bought the boots but my truck came with a different kind of boot. Only problem is that if one of them breaks or is bad and you need to replace it you cannot buy them individually. Ford doesn’t even sell this part number anymore and you have to special order the spark plug if you need to replace one. The gap is closer is closer to .28 but if you’re tuned that’s ok. Honestly for the price and how fast you get them you can’t beat them, but I did have one go bad and I had to pay $13 to try to find one individually at that point you might as well just buy a new set.

Bought these because I was getting my raptor tuned and the cold plugs are recommended. Great choice

Installed these on my 2017 second generation F150 3.5 Ecoboost with 93 tune. Had issues with spark blowout for YEARS. Tried a ton of different plugs. Tried gapping at .020... These plugs worked. I ohmed the plugs when I got them to determine if these were knockoffs/counterfeit. All plugs tested 4-5k ohms. Thats pretty standard. And knockoffs wont read consistently. I did gap these to .020. Use the proper gapping tool (ten dollars amazon). No issues so far. 22psi boost.

Makes my 2017 F150 3.5 ecoboost with a race tune run better than with the stock plugs. Torqued just over the 15ft lb setting with my click torque wrench. Install was a breeze.

Good fit and fast shipping

Direct replacement for my 2018 F150 2.7L Ecoboost motor. 45 minutes and the job was done. Make sure you use dielectric grease on the threads of the spark plugs and do NOT overtighten them.

One of my spark plugs came in with the ceramic broken. For what I read in the reviews it seems like a common issue

Great product came packaged well with a box inside a box and was 11 days earlier then expected. After opening both boxes and looking over the plugs i got what i expected brand new plugs. Replaced the factory ones that had 152,000 on them and no problems with them. Truck is bone stock and there isn't a misfire anymore as i had one bad plug causing a misfire.

I am in utter disbelief on how much of a difference after installing these. I have numerous mods done to my 2018 F-150 limited 3.5 Ecoboost. Was getting some misfire and Inturn sport mode could be a bit choppy and these completely solved that issue. It’s almost like these plugs were the thing needed to bring everything I’ve done to my truck together. If you have a tune BUY THESE! Thank me later

These babies came wrapped in 3 boxes, all packed tightly with bubble wrap so the box they were in with a flimsy carboard divider was very secure! a wrap of foam around each plug wouldn't hurt... The plug came all gapped .030, put them in the truck and she runs great again. don't forget to buy the boots before starting this job! 5/6 of mine were stuck to the old plugs and came out in pieces.

THANK YOU!

I purchased these 6 spark plugs and the packaging was very very poor one of the spark plugs came cracked. I had to order six more in order to have a complete set of 6. While they are a fantastic product they're packaged extremely poorly and I was going to submit for a refund but it was not worth my time or effort.