Lets see who can do the best remote diagnosis.
I'm going to take the car back to the shop on Monday.. we'll see who's right
The stats:
2004 STI
99K miles
Stg II Accessport with OTS tuning
Catted AVO Downpipe
Freshly installed Exhaust cutout just ahead of the muffler.

Yesterday I was driving home from work on surface streets when by 2004 started idling rough and threw a CEL, which quickly turned off
I got the car home and pulled codes using my Accessport
P0021 (advanced timing thing?) , P0304 (cyl 4 misfire), P0303 (cyl 3 misfire)
Checked the oil, it was a little low and a little dirty

This morning I dropped the Garage One for diagnostic and oil change (it was about time).

They didn't really get to dig into the car until this afternoon, and asked me to drive it a little to see what other codes it logs. Apparently it's throwing misfire codes for all 4 cyliders randomly and they want to get a better log.

Their results:
I picked the car up this evening with the CEL light on all of the time and the cruise control light flashing


Now to me, this sounds like a bad #4 coil pack, but the P00021 code implies something else going on.

Thoughts?

 

P0021 can be also be cause by dirty oil or lack of oil changes. Have had a few cars that I worked on with the same cel and did a oil cleaning service which was basically an oil additive you add to the oil and let it sit and idle for 15-20 minuets with fresh oil in it, then dump it out and replace the filter and oil. You'd be surprised on how dirty the oil will come out

 

Probably OCV on the way out. Id suggest not driving it and do what Anthony suggests because OCVs have been linked to a lot of turbo failures as well.

 

What are you using for the oil cleaner? Marvel Mystery Oil?

 

snake oil!

I'm always iffy about additives even if they work. I feel like they could do some long term damage

 

Subaru actually has an oil additive that we use.

 

hmm - deciding if I'm gonna play with this myself, or leave it alone and let garage one finish the job on Monday...
Right now I'm thinking I've already invested in the diagnostic and I might as well let it be their problem.

I keep on finding stuff about the Oil Control values and code P0021... getting sketchy about driving the car

 

Except in this case the info comes from an actual Subaru tech. So I'll go with his recommendation on this.

 

Cam Position sensor, or crank position sensor. Possibly just dirty? Jumped timing? of course IM just throwing random stuff out there and of course just worse case scenario.

 

Also just throwing this out there... the only times I have read of or experienced misfires on all 4 cylinders it was timing related.

Most of the time if you jump timing it shows misfires on both passenger side or both drivers side cylinders... unless your crank sprocket jumped timing.

When my legacy randomly began to misfire on 4 cylinders while driving from Portland to Sac it still drove fine and didnt show any symptoms... just flashed the CEL and popped P0301, P0302, P0303 and P0304. Got back on the highway and about 40 minutes later my Crank Pulley came off entirely even though I hadnt touched that bolt in the 4 years I had owned the car.

Turned out that my car was throwing the misfire codes because my crank pulley bolt started to loosen to the point where the woodruff key would slip out of the crank pulley keyway and then catch again. Besides eating up the backside of the crank pulley, it also caused this to happen in the keyway of the crank sprocket.



The small notch caused my entire timing to be off by a degree or two hence causing the misfire on all 4 cylinders.

Cliff notes: Take 2 minutes and throw a wrench on the crank pulley bolt and make sure it is still torqued down.

 

Found it... debris in the AVCS solenoids; cleaned em out... idle is back to normal CEL's gone.

 

Wow... wouldnt have guessed that. Glad to hear it is fixed!

 

What kind of debris?

 

same thing happened to my FXT, it was weird. I got a new used one and it works fine now but i also cleaned mine up and it seems to work fine.