got a P0300 code today - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

stlgrym3 · 04-05-2019, 09:24 PM

Noticed CEL today, car was driving fine. Plugged my ecutek dongle and used the software to get the code, it was a engine misfire P0300. Googled it and the descriptions were all over the place, from replacing spark plugs to take apart the entire engine. I just used the Clear DTC function of the ecutek ProEcu and now the CEL is gone.

I’m running ACE header with Delicious flex fuel kit and tune. Hopefully this is a one time thing. Any reason I should be concerned? The car only has about 5000 miles. I did just put in a new tank do E85 couple days ago, maybe bad gas?

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maslin · 04-05-2019, 11:16 PM

P0300 is random misfire, no way to diagnose that over the internet. Not much to check since it’s cleared either.

Move on and see what happens, bad gas could certainly do it.

humfrz · 04-06-2019, 04:28 PM

Quote:

Originally Posted by maslin

P0300 is random misfire, no way to diagnose that over the internet. Not much to check since it’s cleared either.

Move on and see what happens, bad gas could certainly do it.

Yes, I agree. Maybe your engine just hiccupped.

If the code doesn't return, I wouldn't worry about it.

If it does return, and you plan on taking your car into a shop, DO NOT erase the code before you take it in. Why not? Because without the code in place, it will limit the shops efforts to diagnose the problem.

humfrz

Kodename47 · 04-06-2019, 07:19 PM

Flexfuel kit, are the logs showing any issues with the output?

Thunder86 · 04-06-2019, 08:47 PM

If it makes you feel better:

I got a P0300 on startup @ 1300 miles (almost a year ago). Took it to a local dealer, they checked the gas to make sure it wasn't watered down (it had been raining heavily for weeks). All was well.

After they cleared the CEL, haven't had any issues since (knock on wood). I'm now at ~10.5k miles.

FRSBRZGT86FAN · 04-07-2019, 05:26 PM

Contact delicious tuning and ask if this is an issue with a tune when it comes in contact with bad fueling that's basically you asking if they've seen this before. Were you running e85, 93 or a mix at this point?

04-05-2019, 09:24 PM	#1
stlgrym3 Senior Member Join Date: Nov 2011 Drives: 2017 Subaru BRZ Limited Location: socal Posts: 562 Thanks: 72 Thanked 51 Times in 44 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	got a P0300 code today Noticed CEL today, car was driving fine. Plugged my ecutek dongle and used the software to get the code, it was a engine misfire P0300. Googled it and the descriptions were all over the place, from replacing spark plugs to take apart the entire engine. I just used the Clear DTC function of the ecutek ProEcu and now the CEL is gone. I’m running ACE header with Delicious flex fuel kit and tune. Hopefully this is a one time thing. Any reason I should be concerned? The car only has about 5000 miles. I did just put in a new tank do E85 couple days ago, maybe bad gas? Sent from my iPhone using Tapatalk

04-06-2019, 07:19 PM	#4
Kodename47 Senior Member Join Date: Oct 2012 Drives: UK GT86 Location: UK Posts: 3,040 Thanks: 185 Thanked 1,629 Times in 1,112 Posts Mentioned: 155 Post(s) Tagged: 1 Thread(s)	Flexfuel kit, are the logs showing any issues with the output? __________________ .: Stealth 86 :. Abbey Motorsport/K47 Tuned Sprintex 210 Supercharger Kodename 47 DJ: Soundcloud / Instagram / Facebook

04-06-2019, 08:47 PM	#5
Thunder86 Member Join Date: Jul 2018 Drives: 2018 Toyota 86 GT trim (Thunder) Location: SoCal Posts: 88 Thanks: 15 Thanked 57 Times in 31 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	If it makes you feel better: I got a P0300 on startup @ 1300 miles (almost a year ago). Took it to a local dealer, they checked the gas to make sure it wasn't watered down (it had been raining heavily for weeks). All was well. After they cleared the CEL, haven't had any issues since (knock on wood). I'm now at ~10.5k miles. __________________ [insert poor quality, phone-taken picture here]

04-07-2019, 05:26 PM	#6
FRSBRZGT86FAN Senior Member Join Date: Jun 2013 Drives: 2023 GR SUPRA,15 FR-S (SOLD) Location: Philadelphia, PA Posts: 4,235 Thanks: 3,086 Thanked 2,100 Times in 1,397 Posts Mentioned: 31 Post(s) Tagged: 2 Thread(s)	Contact delicious tuning and ask if this is an issue with a tune when it comes in contact with bad fueling that's basically you asking if they've seen this before. Were you running e85, 93 or a mix at this point? __________________ SOLDOFT Stage 2 UEL E85/Nameless Performance 3 inch axleback with 5 inch mufflers/ TRD CAI / CNT UEL/ Cusco Strut BAR & LHD Brake Stop / "JDM" Toyota Badges / WinJet JDM headlights - DRL MOD from fteightysix.com - 5000K Diode Dynamics HID kit / Diode Dynamics LED interior Lights and sidemarker bulbs / JDM Clear Sidemarkers / Diode Dynamics LED switchbacks/ OLM LED rear turn signals / Tap Turn RelaySOLD Last edited by FRSBRZGT86FAN; 04-08-2019 at 12:48 AM.

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04-05-2019, 11:16 PM	#2
maslin Benz Tech Join Date: Dec 2018 Drives: 2017 BRZ Premium Location: Oregon Posts: 580 Thanks: 363 Thanked 562 Times in 308 Posts Mentioned: 6 Post(s) Tagged: 0 Thread(s)	P0300 is random misfire, no way to diagnose that over the internet. Not much to check since it’s cleared either. Move on and see what happens, bad gas could certainly do it.

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