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Discussion Starter · #1 ·
Hey all,

I just started having this CEL a couple days ago, used a buddy's OBDII reader to get the code which I put in the title. I bought this car fresh off the lot at the end of 2017 so I've only really been driving it for 3 years/42,000 miles. It's my daily driver and completely stock. I've taken it on longer trips but besides that it's work to home no racing or rally.

Driving to work on Friday the engine sounded like it normally does and I didn't have any issues or weird indications on the gauges.

Any suggestions on how to proceed? Or anybody with experience with this?

Thanks.
 

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Try pulling and checking plugs first.
 

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Hey all,

I just started having this CEL a couple days ago, used a buddy's OBDII reader to get the code which I put in the title. I bought this car fresh off the lot at the end of 2017 so I've only really been driving it for 3 years/42,000 miles. It's my daily driver and completely stock. I've taken it on longer trips but besides that it's work to home no racing or rally.

Driving to work on Friday the engine sounded like it normally does and I didn't have any issues or weird indications on the gauges.

Any suggestions on how to proceed? Or anybody with experience with this?

Thanks.
Assuming you aren't tuned and are stock from your description, did you ever change your plugs out? If not, as Dale mentioned, check that.

You'll need replacement plugs if they were never changed and they'll need to be gapped properly.
 

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Discussion Starter · #4 ·
Aren't plugs more of a 100,000mi change? Or are you saying it could just be a faulty plug. Yes 100% stock it's factory issue condition in that regard.
 

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Aren't plugs more of a 100,000mi change? Or are you saying it could just be a faulty plug. Yes 100% stock it's factory issue condition in that regard.
Lol, not on this platform. They are a 20,000 mile change.
 

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Well ****. So the manual is dead wrong? It says 100k miles.
That manual excerpt is probably part of the standard Focus platform, not specific to the ST. Believe me, for the folks here that are tuned, it's closer to every 10k to 15k.
 

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Discussion Starter · #9 ·
Copy, I get into boost a lot because even though I don't race I still like to push it on every straightaway, corner, and onramp I come across. Gotta make the daily grind fun right?

I'll get the plugs checked out thanks gents.
 

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Yep...start with new plugs and go from there.

Lots of folks here are finding the Ruthenium plugs essentially eliminate cold start misfires that so often plague the Ecoboost platform.
 

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Also make sure to check the gap on the new plugs. I've had some come with a large gap and some perfect. Do .026-.028 and use a feeler, you could use a coin with the marks on it but definitely not as accurate.
 

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Hey all,

I just started having this CEL a couple days ago, used a buddy's OBDII reader to get the code which I put in the title. I bought this car fresh off the lot at the end of 2017 so I've only really been driving it for 3 years/42,000 miles. It's my daily driver and completely stock. I've taken it on longer trips but besides that it's work to home no racing or rally.

Driving to work on Friday the engine sounded like it normally does and I didn't have any issues or weird indications on the gauges.

Any suggestions on how to proceed? Or anybody with experience with this?

Thanks.
A P0300 is a misfire code, the last number indicates what cylinder. Ford manuals give you guidelines, and that’s about as far as I’d go. If you enjoy your car, change your oil every 3k (oil is cheap, turbos and engines aren’t.) change your plugs and trans fluid at your initial 20k miles, I just did mine, I bought a 2018 ST used and it had 18,000 on it and that’s the first thing I did. If you want your vehicle to last, I don’t care what literature you read or what anyone says, change EVERYTHING with the exception of your oil, every 20,000 miles. Oil should be changed in a turbo vehicle every 3k if you want to own the vehicle longer than 5-6 years without long term problems. $30-$40 for 6quarts and a filter is a no brainer. I daily mine and have had no issues. It also helps that im a mechanic and get stuff at price🙌But moral of my story, is preventative maintenance goes a long way when you involve turbos. Trust me.
 
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