Cylinder misfires or bad injectors, please post here.

well my car has been misfiring on #3 for a while you can feel it at idle but not under power. the CEL has come on a few times and goes off after a while. BUT.... Today i started up the car(it was cold here in colorado this morning) and when it was misfiring i could here a knock. not a ticking like lifters but a friggin Knock like metal on metal. I was pretty low on oil so i added a few quarts(2) and the knock went away. So I'm thinking my misfire has something to do with the valves/head on the #3 cylinder. this car has 110,000 miles on it. I want to take it in but i dont want to spend loads of money on them trying to trouble shoot the problem and after they figure it out after who knows how much cash in T.S. cost they rape me on parts and labor. I just have a strange feeling this is gonna be a very very exspensive endeavor. Does anyone know a good Subaru shop in the Denver area they recommend?

33 degrees this morning, and it's idling worse then when it threw the P0304 code. I'm really surprised that I can't get a misfire CEL at this point.

P0302, the fun never stops with this car.

 

I had this code earlier in the year, and they replaced my coil in #2. It was all melted. We replaced the spark plugs with OEM's, cleaned the MAF as well.

 

CEL was off, but the rough idle was there. Everyone said check for a leak. Eventually I got a P0171 and ran a smoke test. BPV leak. I purchased a new gasket and some RTV sealer, and thought I was done with it as of yesterday.

 

I let the RTV cure. I take it for a spin, and still have the CEL. I figured it was vacuum related and the ECU would adjust it self. Today I get the P0302 while pulling in to a parking spot. So I have no REAL idea if the BPV gasket worked or not, so I can't rule out a vacuum leak unless I smoke test or something again. But the code was a no show.

 

BUT as the P0302 was in play (I guess that's how you'd refer to it), my idle dropped from 1k to almost half. 1k is ok, but still missfires. When it hit half, I knew something was wrong. This thing sounded and felt like it wanted to die. Just as it smoothed out, the CEL came on. It seems to run better (but still bad) with the CEL on, than it did before the P0302 code. If that makes sense.

 

I'm taking the car in tomorrow. Anything specifically I should mention aside from having new plugs and coil on #2?

If you did all of that and are still getting a misfire it's most likely the injector or you might have valve issues. Have them do a compression test and see what it comes in at.

I had the fuel injectors cleaned. The car runs smooth again.

If you don't mind my asking, how much was it to have the injectors cleaned?

It was $119, but they did the air intake as well. Took them about an hour.

Okay, I have a good one for you guys....

 

LGT 05, STi swap, running all this for a year now....

 

standard fuel hoses and side feed injectors.

 

Walbro 255 in tank

 

Car has been running fine for ever with no idle roughness or knock present...

 

one day, slight pull, misfire cylinder 4....

 

changed (on both cylinder 2 and 4):

-coil packs

-spark plugs

-injectors

changed the fuel pump assembly seal and metal ring holder

Leak down test on both gave me 10% leak, almost perfect...

Compression test gives a 145, 147 on respective cylinders

Checked for vacuum leaks, cracks....nothing

 

swapped injectors,coils, spark plugs....no change....it persists on cylinder 4, sometimes 2....regardless of swap-arounds....

 

everytime I played with the seal for the fuel pump, it was worst or better, depending on the "seating" of the damn thing...so I sealed it up with urethane(yeah, I know...) and the whole thing was pretty sealed thight....but still the misfire on cylinder 4, but under heavy load only!!!

 

Maps and such are out of the equation as the car ran perfect for a year without any glitches...

 

Car still runs perfect up to 14psi, but no more....no heavy gas consumption or anything that would suggest any problem, until the throttle is squeezed fully...

 

I'm at wits ends....any ideas.?! Please....

 

Thanks for your ideas...

Electrical wiring? Fuel rail? That's the only other variables I could think of. Hopefully others chime in.

Ringlands and/or valves. 10% is not perfect (although it depends on your leakdown tester). Did you do compression/leakdown on #1 and #3 as well?

I did check wiring and nothing seems to be standing out as of now...and I do not think it would only act up on high load.

 

I did not do a leak test on 1 and 3 as they are not showing signs of any roughness or misfires. Can you elaborate on why I should..!?

 

From what I know, 10% leak is pretty standard on a 2.5L... and with 145 compression, I do not suspect anything from the cylinders, a faulty ringland would show a certain sign on the leak down...I think....

 

The only thing I can think of now would be related to fuel... a faulty pressure regulator?!?! a leak in the tank??!

 

Any more ideas or similar experiences...?!

Man it sucks to see this problem still. Its the reason I traded in my Spec B. Every damn winter the same problem, went through multiple injectors, coil packs, and so many parts with the dealer (under warranty) that I finally gave up.

Leakdown test on #1 and #3 would rule out or confirm inconsistency with your leakdown tester. 10% on your gauge could be perfect or you could, in fact, have a bad reading on #2 and #4.

Could try, it only seemed unecessary at the time as the tester was used on a previous car 2 minutes earlier....

 

 

Worst part is, when I had a leak at the tank, it would leak gas and smell real bad, but no codes....!! This is really annoying...

 

Don't know where else to look on this one...

You have to get data from all cylinders, otherwise your leakdown test is worthless (unless the leakdown was super bad like 50% and you could feel/hear air escaping from valves, or via crankcase).

Well the stumbling came back about a week after the fuel injectors were cleaned.

 

It's getting rough enough to the point where I know it's going to throw the code soon. My guess it that it's the exhaust leak I had. Thought I fixed it with a new BPV gasket and RTV. So either that's the failure, or there's another underlying cause.

 

In park or neutral, it RPM's at about 700? But when I'm stopped it drops to that line that's right above 0 on the speedometer.

You could have a vacuum leak or bad ringland/valves as previously stated. Hope it's something stupidly simple.

Well like I said in this thread (or was it another? IDK) I had P0171 code and the smoke test revealed it was coming out of the BPV. That's why I ordered a new gasket, and RTV'd it and let it cure. I got another code shortly after for cylinder #2 and everything came back ok. Figured it might be dirty injectors so I got them cleaned. A week later, back to the stumble/rough idle.

 

I just spent about an hour and a half verbally abusing my engine while removing the TMIC and TB hose double checking every line I saw. Everything was snug and clamps are now super tight.

 

Still rough.

 

Hopefully it's a vacuum leak. If it's ringland/valves, is that expensive?

Depends on what you mean by expensive. In general, it's just better to buy a new OEM shortblock for ringland failure since the labor cost negates the rebuild cost in many cases. Valves Are also expensive. Again, most of this stuff is labor cost.

 

You said you replaced the spark plugs, correct? I had a mystery misfire and it ended up being cracked porcelain on one of the plugs.

I had a cylinder 2 issue earlier in the year and it was replaced because it had melted. At the time they replaced all the spark plugs with OEM. When I brought the car in a few weeks ago they said my cylinders, plugs and wires were good.

 

Expensive as in $500 and up. But with the amount of money I've put in to this thing for repairs over the past year, anything else than an exhaust leak will probably send me to the loony bin.

Just got back. They ran the smoke test, and there's no leak. But it still has the rough idle. I mentioned the ringland/valve issue and they don't do that there.

 

They didn't know of any shops off hand to send me to. The one they USED to send people to (up the road) shut down.

 

So it's not a leak, the MAF, coil packs, injector, plugs, or wires.

FWIW I had "good plug" that was actually bad. It was easy to miss if you weren't looking for it. It doesn't take as much time as you'd think to take out the plugs once you get around to doing it.

I am new to the Subaru thing but looking to learn quick. I've got a 2005 OBXT with 67,000 miles. Just picked up the car at 64K and originally ran great.

 

So recently I've been getting a CEL with the code reading that I have a Misfire on Cylinder 2. I'v gotten the code 4 times now. With that said, I re-gaped the plugs (nobody in town has replacements in stock but I plan to replace them next week) after the 2nd time and rotated the coils after the 3rd trip and it's still same cylinder. Due to everyone's comments on here, it sounds like rotating the injectors may be the next step. Now that it's been getting cold out, It's been running a bit rougher after start-up. It's high-speed idol is decent but not perfectly smooth, but once it drops back to low-speed idol, that's when it gets trough (sometimes will shake the body if rough enough).

 

Can anyone give advice? Also, can anyone tell me step-by-step how to remove the injectors (Pictures help but not critical)?

 

Thanks.

Removal of injectors is very simple. Be sure to use safety glasses and have shop rag to absorb fuel from around the injector if the car has been operated recently.

 

They are held in place with a retaining flange that bolts to the fuel rail. I believe it is a torx bit. Take great care when removing them, as they may strip easily if using a standard driver - a small impact wrench or driver might do this better.

 

Swap the [injector] with another one and also inspect the screen for clogging. I noticed when I pulled mine I had a few specks of material on them. I took the filter screen off and carefully removed the material.

Edited December 13, 2011 by compsurge
said coil, meant injector

Probably a bad injector. I would go to the dealer and purchase one and just swap number 2 out. Or buy one from a forum member.

 

Then you have an extra to send to DW to get cleaned for when it happens again, and it will.

 

They are known to cause misfires and fail. I lost 1-2 during my warranty period.

 

It is better to just get the extra one so you are not disturbing the others. IMHO