P0304 code

[1198S]

I got a P0304 Code on a couple of days ago. I've replace all 4 plugs and the #4 cylinder coil pack and cleared the code.

1 day later the car is still misfiring and the same code pop up again.

Should I replace all 4 coil pack?

[SD_GR]

No.

How did the spark plug look from no.4?

Check the clips and little wire thingies.

[1198S]

The # 4 plug look normal just like the other 3 plugs, I don't get it. No oil or sign of it being lean. Maybe the # 4 injector is clog?

[SD_GR]

It is possible but not as common as a wiring fault or a coil fault, and you have excluded the latter. Is the car stock? Are there mods that would make it likely the code is legitimate (power mods etc.)?

[Donkey]

http://www.clubwrx.net/forums/genera...hp?t=134337553

[1198S]

Car is completely stock. It has 196K miles I've did use injector cleaner. # 4 coil has been replace as well as all 4 plugs. I will double check the wiring.

[1198S]

http://www.clubwrx.net/forums/genera...hp?t=134337553

Thanks for the link, I will do the following.

[1198S]

I've just replaced the PVC valve, cleaned the MAF sensor with CRC MAF cleaner and I've also cleaned all 4 of the coil pack plugs. I will pour in a bottle of Sea Foam in the fuel tank and see what will happen next.

As of now it is still not a smooth.

[1198S]

I got the same code again today P0304 it is ticking me off. I'm starting to dislike Subaru.

[fortunesk89]

fuel grade? how fast does it recode? try to ohm the injectors or swap with a different cylinders injector

[1198S]

I only use premium grade fuel. It recode about every 100 miles. I'm thinking about replacing the # 4 injector. I'll try new inject cleaner for a few more tanks to see how it does. If not I'll replace 1 injector.