Misfire, Checked everything?

**2manysubies** · #1: 03-06-2012, 08:55 AM

05 LGT stock, P0302, changed plug(all were changed before I bought car)
changed coil pack(subaru)
changed injector(subaru)
Did comp check 125psi(same as other 3 cyl. +/- 2psi
checked coil connector and re-routed wire a bit
checked for vac. leaks @ manifold/head area(spray method)
removed TMIC, checked for Vac. lines/leaks/cracks
Nothing out of place or "odd" looking...
I'm at my wits end.

WHAT AM I MISSING???

R/Mac

**2manysubies** · #2: 03-06-2012, 08:58 AM

OBTW, the car runs good, doesn't feel like its misfiring, gets CEL, sometimes the CEL blinks on/off before it goes on steady, did clean the MAF/IAT

**bmx045** · #3: 03-06-2012, 09:07 AM

maf sensor, clean it

**GTTuner** · #4: 03-06-2012, 11:08 AM

Cylinder leak down percentage.

**20lgt06** · #5: 03-06-2012, 04:45 PM

i was battling the same issues, did all off the above- ended up with a burnt valve. does your rpm dip? vac leak check bov or on your year the blue t fitting?. when they changed the injectors did they use all new gaskets and orings? also check voltage coming off the harness. checked your intake ? pvc assembly replaced? bad or clogged cat? fuel filter clogged? just to throw out a few others i would check. is that the only code ?

**suds2250** · #6: 03-06-2012, 05:01 PM

Is the problem at idle, and get better at high RPM? I had a similar issue, the engine would act like it was running on two cylinders. Turned out to be the oil control valve (OCV) was sticking, causing the timing to be way off.

**2manysubies** · #7: 03-07-2012, 10:17 AM

Thanks for all the suggestions! The CEL comes on randomly,more often when it's cold out(all the time right now in Maine LOL) when it's acting up, Idle is rough. I did remove the TMIC and checker the blue T vacume, thew BOV sems intact, will do a vacume check on it, the injectors were new and new "O" rings. I didn't check the pvc, but I will. What voltage are you refering to on the harness?? Vacume check did not indicate a bad cat. I have a leak down tester comming, don't want to borrow one from the shop in case it breaks, I own it $$. As far as the oil control valve, how do I check it? Location? I do ALL my own work on my subies, but this is mt first Turbo, I am getting quite intimate with the system as we speak. Thanks for all the help again. Compression was 124-126psi, is this normal for a higher milage motor?? For my last answer, P0302 is the only code I get.

Thanks again
R/Mac

**suds2250** · #8: 03-07-2012, 07:37 PM

There are lots of threads on the OCVs

http://legacygt.com/forums/showpost....28&postcount=8

**snowboardr424** · #9: 03-07-2012, 07:51 PM

I had a strange cylinder 4 misfire on my old wrx...I would only get the misfire at a cold start up (never moving,) maybe a week or more in-between lights.

I cleaned the iacv, crank sensor, cam sensor, maf, you name it...the culprit was the front o2 sensor at 70k.

**2manysubies** · #**10:** 03-08-2012, 07:06 PM

OCV's checked today, cleaned, actuated (12v electric) and manual movement to check for binding, vacume check BOV good, waiting on leak down tool (shipping now) removing TMIC again tomorrow, better check for lines, fittings, cracks etc...

Mac

**suds2250** · #**11:** 03-08-2012, 08:19 PM

Good to hear. How/when did the misfire code happen? what condition was the engine running at? (RPM, load). Has it happened since?

**2manysubies** · #**12:** 03-08-2012, 11:08 PM

Usually when the car is slowing down to a stop, I can feel a slight vibe(miss) in the steering wheel when driving normally, I just know I'm gonna get the CEL, 9 out of 10 times I'll get the light within a few minutes. If I nail it when it's doing the vibe thing, it scoots like hell, no misfire at all, even with the CEL on it runs good when I get on it. Another thing, if I clear the code with the scanner(which I keep in the car) I may get a CEL in a few hours drive time, if I disconnect the battery for about 20 minutes, the car runs sweet for days, the ECU is learning bad habits from somewhere, I only use Mobil hi test(91) with 10% ethanol, same station. I really want to put 5 gal of 100 low lead(aviation fuel) in mixed with the rest pump gas and see how she does. I WILL get to the bottom of this, I never give up, it's only a machine! Feel free to PM with any suggestions, and Thanks!

R/Mac

**20lgt06** · #**13:** 03-11-2012, 03:57 PM

are you running a stock top mount ? check the throttle body hose and the ring gasket that goes into the stock tmic

**2manysubies** · #**14:** 03-12-2012, 10:44 AM

I've had the TMIC off already, everything seems in order, I'm gonna take it off again to check PVC system, I'll take another look. Thanks!

Mac

**2manysubies** · #**15:** 03-15-2012, 03:05 PM

OK, Got my leak down tester, checked with engine at op. temp, only checked the #2 Cyl. Total leak down:

1st test = 14% held steady.

Switched adapter hose to apply 100psi to cylinder(seat rings a bit) TDC verified on compression stroke.

2nd and 3rd tests = 12%

Checked compression again 4 cranks 125psi

I didn't hear any leaks from the usual places, exhaust, oil fill etc. I don't think the issue is mechanical, I guess this falls into the "Subaru stumble" catagory, havn't got a CEL in over a week. driving real smooth 21mpg(mixed) I'll keep looking, think I'll check the brake booster for vacume requirements. ALL SUGGESTIONS WELCOME!!

Mac