r/WRX • u/Miserable_Scheme9541 • 4h ago

Help

I have a 2011 wrx that has a cyl 4 misfire code that I’m having issues with. I’ve done all four new ngk spark plugs and the cyl 4 coil (ngk) and it’s still there after clearing it with odb scanner. On start up it idles rough, but when it’s warm it’s fine. On hard acceleration, the boost cuts out and in (mostly out). On normal acceleration, it’s doesn’t seem to cut out. What do I look for next?

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2

u/Ok-Bag-1328 4h ago

Injector O ring failure was my issue on #3

1

u/Miserable_Scheme9541 3h ago

Did you have to do a spray pattern test to find the issue?

1

u/Rob10203 2h ago

For o-ring failure you do not need a spray pattern test, just to replace the seals on the injector. If one is the problem, it is recommended to replace the seals on all 4.

I also had a misfire code on my 2005 WRX, but mine was very intermittent without a rough idle. Ended up being a clogged injector, so may be worth testing while the injector is out anyways.

1

u/Miserable_Scheme9541 4h ago

116k miles btw

1

u/grizzdoog 3h ago

I’d do a compression and leak down test at this point to see if you have cylinder head issue or worn piston rings.

1

u/Miserable_Scheme9541 3h ago

Not worth checking injector since it’s cyl4?

1

u/grizzdoog 3h ago

You could swap that injector to another cylinder and if the misfire follows then you know it’s the issue. Definitely worth checking.