Author Topic: Brief CEL code P0304  (Read 964 times)

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Offline silverUURX

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Brief CEL code P0304
« on: June 28, 2017, 09:10:39 PM »
So cruising down the crowchild this evening. 4th gear in sport mode around 80km/h. I looked down at the dash to see a CEL and a flashing sport. Shift into 6th and I switch into "i" and then CEL and flashing sport are gone... Accessport shows nothing out of the norming as for Fine knock and DAM. Get home and pull into the garage to see the P0304 which is misfire on 4.

Anyone else every seen anything odd like this?

I've been  on stage 2+ 91 ots tune for probably 60000 kms now. Car currently has 95000kms.

Offline RockThePylon

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Re: Brief CEL code P0304
« Reply #1 on: June 29, 2017, 01:09:45 AM »
Keep up with the service schedule?
I may scream like a dainty lady, but I punch like a fairly strong 11-year-old.

Offline silverUURX

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Re: Brief CEL code P0304
« Reply #2 on: June 29, 2017, 07:05:52 AM »
Been running motul since I got the car. Change it between 5000-6000kms.

Clean the air filter every 2nd oil change.

Changed the diff and tranny fluids to Motul around 70000kms.

Haven't touched plugs or injectors yet though.

Once I've had to top up the Oil after a long trip from calgary to whistler then back through the kootneys. So tons of elevation change and switched maps and started running Shell 91 after that road trip because I found the 94 tune knocked a lot.

Offline Delphiwrx

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Re: Brief CEL code P0304
« Reply #3 on: June 29, 2017, 03:52:20 PM »
Check cylinder roughness on that cylinder and see if it counting at all.
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Offline RockThePylon

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Re: Brief CEL code P0304
« Reply #4 on: June 29, 2017, 09:55:02 PM »
Plugs are about due. Easy first step.

Check the gap on the old plugs too.
I may scream like a dainty lady, but I punch like a fairly strong 11-year-old.

Offline wrxsti15

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Re: Brief CEL code P0304
« Reply #5 on: June 30, 2017, 07:40:52 AM »
Spark plugs are 100000 km if you do not tune car... This is what Airboy recommended...
30,000km on the stock plugs should be OK for tuning.  Once tuned, change them at 50,000km and then every 40,000km after that.  Use OEM Iridium plugs.

Offline StreetsTheWay

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Re: Brief CEL code P0304
« Reply #6 on: March 11, 2018, 06:30:39 PM »
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I figured since my findings are directly related to this topic, I'd add on for anyone searching out there. O0

Over time, the brief CEL flashes you may get under low engine load accelerating from 1st gear may develop into a constant on CEL. (P0302 and/or P0304). ECU detects severity of the occurrence essentially.
These are common on the driver's side bank [Cylinders 2&4], not sure why, but there is a very strong consistency that I have found talking to people and searching on other forums.

If you get these symptoms under these conditions:
#1. Remove, Inspect, and likely replace with OEM spec spark plugs. Inspect leads for any contamination or corrosion just to stay safe. (This was the solution to my problem - just needed new plugs!)
#2. On an engine that hasn't had an air/oil seperator on it for 90,000+ kms, there is a chance that the exhaust valves are starting to get fouled and nasty. A friend of mine had this issue with a 2007 STi and this was his problem even after replacing spark plugs. Sounds odd, considering we had the same CEL code appear under the exact same conditions for seemingly totally different problems.
#3. Reading through NASIOC and IWSTI, other forums, users suggested cleaning MAF, checking and replacing MAF if necessary and a few other suggestions that didn't correlate with the conditions in which my symptoms would appear if you really think about cause and effect. Take what information you find on forums into consideration, but not as a cure-all solution to all your problems.

Hope this helps someone out there.