Cylinder #2 Misfire

[LegacyGT_in_VT]

Hi,

 

So I just bought a 2005 Subaru Legacy GT with 139,xxx miles on it. The place I bought it from said it was throwing a Cylinder #2 misfire, but that they changed the coil pack and it seemed to fix the problem. Well lo and behold, I was driving it 3 days later (approximately 150 miles since purchasing) and the check engine light comes on steady with flashing cruise control light. Since this is my first Subaru I didn't know what that meant, but soon learned that it was a type of "limp mode".

 

I brought it to AutoZone and and they plugged the code reader in and it again showed Cylinder #2 misfire. Alright, well then let me buy some spark plugs and change them. I decided to go with Bosch Super Plus copper plugs even though OEM called for Laser Iridium (since I don't mind changing the plugs more often).

 

This was my first spark plug job, but thankfully for this forum I found a few threads on changing them and was able to change them no problem! One thing to note, cylinder #1,#3, and #4 all had NGK plugs, whereas cylinder #2 was an AutoLite. Didn't really think much of it at the time, but I now have a theory of why that was the case. As an aside, I did make sure to gap the plugs to 0.044".

 

I inspected the coil packs and sure enough cylinder #2 had a new coil pack, and the other three looked a bit rusted, but nothing terrible (and no codes) so I just reused them after applying some dielectric grease.

 

So I put everything back together, and since my battery was disconnected for several hours it reset the codes and nothing popped up right away. I figured that I needed to drive a certain number of miles to have a drive cycle the computer could analyze, but I could tell there was a misfire. I went to the local GM dealership and bought a can of BG44K injector cleaner hoping that by some miracle it would clean things up and my misfire would go away, but at ~200 miles the check engine light came on with the blinking cruise.

 

I decided to go and purchase a code reader (even though supposedly this car can show the codes on dash) I just couldn't easily find the green/white connectors under the dash, and decided that it would be handy to have a OBDII reader around.

 

I plugged in the reader and sure enough cylinder #2 misfire!

 

So my next step was to change injectors. I swapped #1 and #2 injector hoping for the misfire to follow, but nothing. Code reader showed pending cylinder #2 misfire. Although, I will admit the car ran noticeably rougher at idle, so I swapped the injectors back to their original position.

 

I've been doing a lot of reading on the forum here, and I'm pretty scared of what the diagnosis might be. I mean, I guess I won't know for sure until I bring it somewhere, but I don't have lots of money and need to save as much money as possible. Am I correct in thinking it's a burnt exhaust valve?

 

I just don't understand how I was able to drive the car home from the place I bought it from and not feel a misfire. The car pulled good, and had no signs of misfire.

 

What should my next step be? Compression test?

[freaksavior]

Sounds like you've done some research, good on you. Also, welcome to the forum.

 

I decided to go with Bosch Super Plus copper plugs even though OEM called for Laser Iridium (since I don't mind changing the plugs more often).

 

I don't know if this would actually affect it, but personally I would have gone OE.

 

I did make sure to gap the plugs to 0.044".

 

Stock gapping is supposed to be 0.038 0.031, although copper may be different.

 

What should my next step be? Compression test?

 

Did you change the coils around too? I would do this as well as a compression test for the next troubleshooting step. If it shows good, consider a leak down test for each cylinder.

Edited August 2, 2016 by freaksavior

[LegacyGT_in_VT]

I actually haven't changed the coils around yet, because it is supposedly a brand new coil pack on cylinder #2. Just for laughs though, I will swap them when I get a chance, just to rule it out, but I will then do like you say and run a compression test.

 

I have a friend that has a well drilling business and has a garage / lift that I can use if it comes to having to pull the engine. However, I want to have all my ducks in a row because I can't tie up his garage for an extended period of time.

 

I haven't looked for shops in the area, but living in Vermont I'm not sure what kind of luck I will have as far as "quality work" or a shop that "specializes" in EJ255's.

[ehsnils]

Considering the age/distance your car has I'm not surprised that there are some problems developing.

 

And I would definitely use the OEM plugs with correct gap. "Reading" the plugs would also give some clues to what the problem may be.

 

Cleaning MAF and checking for air leaks like cracked hoses or bad clamps are steps to start with. The donut gaskets on the manifold are notorious culprits but they usually manifests themselves with bad cold idling.

 

A compression test is also important, but even if it checks out you may have too narrow valve clearance, which has to be taken care of before you burn a valve.

 

If you get bad compression on one cylinder (probably #2) then if you are lucky it's a burnt valve. However if you have a burnt valve then you shall have the injectors checked/cleaned/matched professionally. Or get a new matched set depending on what's cheapest and easiest.

 

If you work on the heads it's worth to take care of both heads and replace seals and check clearances. It's good if you can do most of the job yourself since it will save you money.

 

If you aren't lucky and have bad compression it's a piston issue.

 

My experience is that Subies are pretty common in Vermont, so check around in local forums for shops with good reputation.

 

And if you take apart the engine check the turbo for any axle play and the banjo bolt filter.

[MAP]

I have to do my own troubleshooting. I have a misfire on #2 as well. I'm at around the same mileage, 138,900. I've replace the plug and coil and still get a misfire/rough idle but only when cold. Once the engine warms up the idle smooths out. I'm hoping it's a bad o-ring on the intake manifold that seals up once the engine warms up. You would think a bad coil or plug would get worse as the engine warms up.

[Max Capacity]

I thought the plug gap is .028 ?

 

Only use the NGK plugs called for or one step colder. I use one step colder.

 

Contact Brian at http://www.tuningalliance.com/home.html

 

Tell him I sent you, he can get you the right parts and help you with the codes and tuning when it comes time.

 

There is a member from the Killington area, I'll try and find his info. No sorry I deleted the PM's.

 

Did you get the car from the Subaru dealer there in town ? I spend most winter weekends in VT and we sometime do diner and movie in Rutland.

 

http://people.csail.mit.edu/ilh/vacation/ the 2005 GT start around page 1605.

 

 

 

These cars are known to burn valves in #2 or #4 cylinders, or break piston ringlands.

Edited July 31, 2016 by Max Capacity

[LegacyGT_in_VT]

Thanks for the reply! Killington is right next to Rutland, so would be cool to have someone local.

 

Yeah, I've been kicking myself for installing the Bosch coppers, but thought it'd be alright so long as I gapped them properly. I'll get a set of the NGK Laser Iridium's in the next couple days and replace them.

 

So, say I end up repairing everything, and the codes all go away, what do I want to do for a tune? If I read correctly, the stock tune is what is causing some of the issues? I lived in Connecticut for a while (Litchfield), so I'm not afraid of making a trip / dealing with someone from down there.

[Max Capacity]

TA is one of the best if not the best Tuner for these cars. Really he's that good.

 

Contact Brian and he'll help you out, when it comes time Mike Kinsman will do your tune.

 

Reach out to Brian.

 

They have big news coming soon.

 

Another good person to buy from is "Underdog" PM him.

 

 

 

I ski at Okemo, season pass holder for 20 years.

[LegacyGT_in_VT]

I actually bought the car in northern Vermont (near Burlington). When I got the title, there were 3 different people who owned it without registering it. They were all car dealerships, but I just thought that was weird. Seems to me like people would buy it, try to fix it, realize it was gonna cost them more than they wanted to spend and would sell it to the next sucker. The final one being me. LOL

 

I admit, I hadn't done tons of research on the Legacy GT's. I knew they were fun to drive, and always wanted one, but foolishly bought the car without researching the forums.

 

The first thing I noticed when I inspected the car was that it was missing the engine cover, and the hood prop clip was missing so it's just resting inside on top. If I knew what I know now, I could have had some serious bargaining power, but you live and you learn.

[Max Capacity]

As said above, a compression test may be in order.

 

Make sure all the vacuum hoses are tight and not leaking. Is the MAF clean ? Use MAF sensor cleaner.

 

Your doing the right thing in swapping injectors and coils one at a time and see if the CEL follows.

 

 

Do the free things first before you spend more money.

 

Can you do a boost leak test ? Plug the hose coming off the air filter box with a pint size paint can, pull the small hose off the blow off valve and give it a quick short blast of air from a air compressor, put your thumb and listen for leaks. When you remove your thumb after a few seconds you should hear air rush out.

 

 

Oh done worry about the top engine cover, I took mine off two weeks after I bought my 2005 GT wagon. I bought the car new late June 2004.

Edited July 31, 2016 by Max Capacity

[BrianEarlSpilner]

What you're describing sounds eerily similar to my experience with burned valves. Also seems shady that 3 stealerships passed it off. I would go straight to the compression test and go from there. If so it's not the end of the world. Use it as an excuse to do some mods as well.

[freaksavior]

I thought the plug gap is .028 ?

 

Only use the NGK plugs called for or one step colder. I use one step colder.

I had read .032 and that's what I ended up gapping my one step colder at. I should have just checked the service manual.

 

 

Also found which said .030

http//forums.nasioc.com/forums/showthread.php?t=518633

 

But official Vac pix say

 

Manufacturer and type NGK: ILFR6B

Thread size (diameter, pitch, length) mm 14, 1.25, 26.5

Spark plug gap mm (in) 0.7 — 0.8 (0.028 — 0.031)

Electrode Iridium

 

Edit- one step colder are also 0.031 by default according to ngk

https://www.ngk.com/product.aspx?zpid=9875

Edited August 1, 2016 by freaksavior

[Max Capacity]

Oh Yea, NGK's site. I forgot about that. We referred to that a lot back in the high boost Honda days. FWIW we used to gap the plugs at .018 so we wouldn't blow the spark out.

[LegacyGT_in_VT]

Alright, so I just picked up a set of these and will try to install them tomorrow evening. I will do that and swap coils, and then it's time for compression test!

[Max Capacity]

Good deal, let us know the results.

[ehsnils]

Alright, so I just picked up a set of these and will try to install them tomorrow evening. I will do that and swap coils, and then it's time for compression test!

 

If you drive the car with the plugs in before taking the compression test, then make sure you take a pic of each of the plugs when they are out for the test. Then post the pics.

 

It could be a good lead too.

[LegacyGT_in_VT]

So, I'm in complete shock. I swapped the Bosch copper plugs with the new NGK Laser Iridiums and changed the positions of the coil packs, and currently have 0 codes.

 

The car runs MUCH better, with no noticeable misfire, but I just don't understand how changing the plugs to Laser Iridium and switching the coil packs around fixed the issue.

 

I just took the car down to fill it with gas and came home and everything feels good. I haven't done a compression test yet, but will run one just so I can know where things stand.

[Max Capacity]

Take the car for a good ride down rt7. Give it a good 20 miles round trip ride at highway speeds.

 

You have learned what many of us have known for many years, NGK's or don't bother. Boosted Honda's seem to have the same result.

[LegacyGT_in_VT]

LOL about Route 7, I drive on that road daily! I will definitely go for a little drive when I get a chance -- check things out at highway speeds, but I'm pretty excited to say the least.

 

Another thing I had a question about was the banjo bolt filter. I have a 2005 so do I want to remove the filters? Or? You also recommended Motul gear oil for the 5 speed?

[Max Capacity]

Yes remove the banjo filters or at least the one on the passenger side head.

 

Yep, Motul 300 Gear.

 

Contact Brian at http://www.tuningalliance.com and tell him I sent you, and you want Motul 300 for your 5mt and rear diff.

 

The stuff is not cheap but its currently the best stuff for these. He'll send you the right stuff.

 

It's hard to get all the old fluid out. the car needs to be put at different angles, front down, front up back down, seems like that needs to done a couple times. Don't worry, start checking the level of the tranny fluid after you put in 3 qt's.

 

The rear diff takes .8qt

 

Make sure you can remove the rear fill plug before you pull the drain plug. Do not over tighten the fill plug.

 

Oh. I use a suction gun as the funnel to slowly allow the oil into the tranny, don't try and push it in, it will over fill the fill tube.

https://www.google.com/search?sourceid=chrome-psyapi2&ion=1&espv=2&ie=UTF-8&q=suction%20gun&oq=suction%20gun&aqs=chrome..69i57j0l5.2950j0j8

Edited August 3, 2016 by Max Capacity

[ehsnils]

I just took the car down to fill it with gas and came home and everything feels good. I haven't done a compression test yet, but will run one just so I can know where things stand.

 

Definitely a good idea.

 

Nice to see that things worked out.

 

And it's my experience as well that NGK plugs are a lot better than others, even though spark plugs seems to be a no-brainer tech experience says otherwise.

[Brady]

I swapped #1 and #2 injector hoping for the misfire to follow, but nothing. Code reader showed pending cylinder #2 misfire. Although, I will admit the car ran noticeably rougher at idle, so I swapped the injectors back to their original position.

 

I'm not sure how to read this. Once you swapped injectors, did you still get the misfire on cylinder 2? Or was it just running rougher? Also, did you use new O-Rings for the injectors when you moved stuff around?

 

I was having a misfire issue about 18 months ago. I did a lot of the same things you did, starting with plugs, then moving coils. The day I was about to swap injectors, the throw out bearing seized. While the shop had the car to replace the clutch, I had them swap #2 and #4 injectors (it was a tough pill to swallow having to replace the clutch while not knowing if my motor was on the way out). The shop was CERTAIN that it wasn't the problem, but indulged me anyway, and told me they used new O-Rings.

 

Wouldn't you know, 18 months and about 30,000 miles later, the CEL has never come back once.

[Stphnhrrng]

So, I'm in complete shock. I swapped the Bosch copper plugs with the new NGK Laser Iridiums and changed the positions of the coil packs, and currently have 0 codes.

 

The car runs MUCH better, with no noticeable misfire, but I just don't understand how changing the plugs to Laser Iridium and switching the coil packs around fixed the issue.

 

I just took the car down to fill it with gas and came home and everything feels good. I haven't done a compression test yet, but will run one just so I can know where things stand.

 

So is the problem completely fixed now? I have the same problem in my ‘08 legacy non turbo. cylinder 2 misfire. Changed plugs to NGK iridium, new OEM coil pack, new injector in cylinder 2, still have CE light. It already had newish NGK plug wires but I just replaced them as a last ditch effort before doing a compression test and having to tear apart my engine. A couple days after the new injector, I cleaned both connections for cylinder 2 plug wire and a few hours later CE light turned off and was gone for a couple days, and ran better during that time. But it just came back on so Idk. I’d like to think it could be a sensor or maybe a wiring issue but I have a hard time believing there wouldn’t be more codes. Does anybody know if there’s a way to check the wiring connections with a voltage tester or something?

[apexi]

So is the problem completely fixed now? I have the same problem in my ‘08 legacy non turbo. cylinder 2 misfire. Changed plugs to NGK iridium, new OEM coil pack, new injector in cylinder 2, still have CE light. It already had newish NGK plug wires but I just replaced them as a last ditch effort before doing a compression test and having to tear apart my engine. A couple days after the new injector, I cleaned both connections for cylinder 2 plug wire and a few hours later CE light turned off and was gone for a couple days, and ran better during that time. But it just came back on so Idk. I’d like to think it could be a sensor or maybe a wiring issue but I have a hard time believing there wouldn’t be more codes. Does anybody know if there’s a way to check the wiring connections with a voltage tester or something?

 

Quite a few bad reviews for those NGK wires on amazon, which echo the experience I had. Ditch those for oem.

https://www.amazon.com/SUBARU-IGNITION-LEGACY-IMPREZA-FORESTER/dp/B00D8I9FNE

 

https://www.amazon.com/NGK-55004-FX101-Spark-Plug/dp/B001RLZ6FU/

[rhino6303]

0.031 is for the turbo models. I have an ‘08 legacy non turbo and gap is 0.044

Gap for non-turbo is 1.0-1.1mm (0.039-0.043"). Edited January 5, 2021 by rhino6303
Removed part number FR5AP-10 or NGK 6371