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Discussion Starter · #1 ·
I have read through many posts about this subject, but they all seem to be older and don't contain any new info, so I apologize for this beaten subject.

I bought my 16 FoST last in March of 20 and it only had 15,600 miles on it at the time. With it being a tad over a year later, I haven't even put 5k miles on it cuz I'm currently sitting at 20,200. I went to leave work the other day and I noticed a CEL after I started the car. I pulled the code with OBD reader and found out it was a P0300, so i erased the code since the car seemed to run perfectly fine after it idled down and I drove home without any power loss or shuddering. I had to run several errands that day and the code didn't come on again, so I chalked it up to cpu hiccup. Low and behold, I went to leave work the following day and bam, the CEL popped up again. This time, I went ahead and replaced the stock plugs with NGK Ruthenium, which came pre-gapped from Tune+, reset the KAM and the OBD code and the light didn't return. I again ran a few errands within a few hours and still no problems. Today, I went to leave to go to work and bam, the CEL returned again. Each time the code appeared was after a cold start, but when the car idled down, it seems to run fine.

The old plugs were pretty burnt, but they all had consistent wear and there wasn't any oil present, just the normal carbon buildup. I pulled the oil dipstick/cap and there was no milky substance present either. At this point I'm at a loss on what to do next. I am supposed to leave for Chicago on the 25th, which is an 800 mile trip, but I definitely don't want to create unrepairable damage amongst my travels...

Any help would be greatly appreciated!
 

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Do you have any mods?

These engines are known to get build up on the valves because of the DI and cause start up misfires.

See here in this explanation
 

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Discussion Starter · #3 ·
Do you have any mods?

These engines are known to get build up on the valves because of the DI and cause start up misfires.

See here in this explanation
I appreciate your answer. I have thought about carbon buildup, but my light cleared after a couple drive cycles after I changed out the plugs. I am going to go ahead and change the purge valve while I'm at it since that seems to be an ongoing problem as well.
 
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