On a scale of meh and Full panic over DTC's....

[xrocket21]

I’m guessing the tune doesn’t like your plugs

i agree. check that gap

 

[isis]

I’m guessing the tune doesn’t like your plugs

Yep. I’ve seen plenty of ‘pre-gapped’ plugs not have even close to the right gap. And also, their specified gap doesn’t agree with OEM or tuner. Good first step.

 

[RustyNutz]

Replacements ordered

 

[DINOZR]

Can someone educate me on why plugs would be changed with so few miles? Does the tune make use of them to produce more power?

 

[1BAD454SSv2]

Can someone educate me on why plugs would be changed with so few miles? Does the tune make use of them to produce more power?

Higher boost with tune and high rpms eat plugs. As gap opens up its harder for spark to jump gap puts more stress on your coils as well. My 14 ecoboost, I would change plugs every 10,000 miles. If I waited till 12,000 miles , started getting misfires. If you puttz around and drive with little boost and lower rpms plugs would last longer but that ain't no fun.

Smaller gap less voltage needed to jump gap and easier on your coils. Short read link below

https://mooregoodink.com/big-plug-g...ite-the-opposite-simple-advice-for-beginners/

Still doesn't explain OP 750 miles , unless he has bad coil or gaps were not set to .25 thousands when installed.

 

[1BAD454SSv2]

The p0018 and p0021 have to to with crankshaft and cam positions. I'm thinking timing chain stretch.

 

[DINOZR]

Higher boost with tune and high rpms eat plugs. As gap opens up its harder for spark to jump gap puts more stress on your coils as well. My 14 ecoboost, I would change plugs every 10,000 miles. If I waited till 12,000 miles , started getting misfires. If you putt around and drive little boost and lower rpms plugs would last longer but that ain't no fun.

Smaller gap less voltage needed to jump gap and easier on your coils. Short read link below

https://mooregoodink.com/big-plug-g...ite-the-opposite-simple-advice-for-beginners/

Still doesn't explain OP 750 miles , unless he has bad coil or gaps were not set to .25 thousands when installed.

Many thanks. This is the context I was looking for!

 

[richnot]

2018, 17k miles. MPT 93 tune with about 1k miles used, and M-12405-35T plugs installed about 700 miles ago. TBH, i swear the idle suffered a bit when I changed the spark plugs: I checked all gaps but have always been a bit suspicious that one may be not quite right. I noticed the spark advanced shown in the Nguage will bounce at idle, since the plugs

I put a GearHeads 93 tune in my 18 and ordered pre-gapped plugs along with it. I ran the tune and 93 octane fuel and the stock plugs and idle was smooth as stock. I had put a few hundred miles on it and then I changed to the colder Ford plugs M-12405-35T that were pre-gapped by GearHeads and the idle was a little rough but then it seemed to smooth out after I put some miles on it. Does the factory computer take time to make adjustments when you change to cooler plugs?

My factory plugs were gapped at 0.28
No other mods other than a drop in filter

 

[RustyNutz]

The p0018 and p0021 have to to with crankshaft and cam positions. I'm thinking timing chain stretch.

I saw that, but just as often is a sensor not agreeing with what it is seeing, or a stuck solenoid. I've driven about 40 miles since the clear, and everything feels normal. I would assume chain stretch/jump wouldn't get better nor go back to how it was

 

[1BAD454SSv2]

Colder plug will tend to have rougher idle . I always disconnect battery when changing plugs . At start up computer relearns everything. Drive about 15 miles normally before boosting it.