music.to.kill.yourself.by Posted July 15, 2007 Share Posted July 15, 2007 All... My '05 LGT LTD wagon developed the stuttering issue sometime last year -- or at least it got worse, with around 25k miles on it. I got it reflashed and it addressed probably 90% of the problem, and I was satisfied with that. But soon after, it started developing an idle misfire which only occurs after the motor is hot from driving at least 10 minutes. Long story less long, at 35k miles the dealer (in Painesville, OH -- shouldn't be hard to figure out) looked at and gave me the usual chickensh*t line of "There aren't any codes, so there must not be anything wrong with it." I took the car out on the freeway, got it hot and brought it back. We all stood around the exhust pipes and listened to the distinct misfire which you'd only *not* be able to hear and see (from the shake which permeates the whole chassis) if you were Hellen Keller. The service manager tells me, "If it were really a misfire, it would throw a CEL." Me: "What would you call that?" -- I asked of the tech. Tech: "A misfire -- and a pretty bad one." Me: "The someone had better get someone from Denso on the phone and tell them that their ECU is f*cuked up, because it can't hear that msifre." Them: [blank stares with hands in pockets] So... Now with 47k miles, it's bad enough that I really can't stand to drive it. I've just read the walk through on spark plug replacement, so I'll probably be doing just that once I can source a set of plugs. No dealership in the greater Cleveland area seems to have any in stock, and subarparts.com has low stock. Maybe I'll stop by the motorcycle dealership which surely has to have them... Link to comment Share on other sites More sharing options...
qikslvr Posted July 16, 2007 Share Posted July 16, 2007 You should be able to get the plugs from NAPA if you have one. That where I got mine. You should also be able to do some datalogging(or have the dealer do it). Believe it or not there is a "rough idle sensor" for each cylinder but it is not a CEL code, but rather a sensor reading. I was getting a rough idle flag from cylinders 1 and 4 and my car would shake too. After changing my plugs at 30,000; they went away and the car run smooth now. FYI these sparks plugs were designed specifically for our motors. I was told that no one carries them on hand because "they haven't needed to replace any since most of the 05+LGTs haven't hit 60,000 miles yet." When I changed mine they didn't really look bad at all, but it did make a BIG difference in how it runs. Let's kick this pig! Link to comment Share on other sites More sharing options...
outahere Posted July 16, 2007 Share Posted July 16, 2007 the plugs are available at sparkplugs.com. Link to comment Share on other sites More sharing options...
music.to.kill.yourself.by Posted July 16, 2007 Author Share Posted July 16, 2007 Thanks for the info, guys. Link to comment Share on other sites More sharing options...
Legacy05 Posted July 16, 2007 Share Posted July 16, 2007 Btw, it could be a bad fuel injector, my car ran into a similar issue .. the dealership wouldn't do squat until the car threw a code. Two weeks later, it finally did .. same thing with my wife's FXT ... her car idled rough for almost 2 months before the check engine light finally came on. Link to comment Share on other sites More sharing options...
outahere Posted July 16, 2007 Share Posted July 16, 2007 My 05 wagon with 16K miles also has the idle misfires, but no CEL. Dealer service "could not verify the problem". Changing the spark plugs did not reduce the misfiring. I replaced one injector and noticed some improvement. I plan on replacing the other 3 injectors. Link to comment Share on other sites More sharing options...
Opie Posted July 17, 2007 Share Posted July 17, 2007 Every dealer now has the Subaru Select Monitor 3 (SSM3), if you are having what feels like a misfire while driving have them test drive the car while monitoring cylinder roughness with the SSM3, the cylinders that shows roughness is the one with the bad injectors. Many dealerships just don't realize how easy the SSM3 can make their jobs and don't bother to get trained on it. Link to comment Share on other sites More sharing options...
whitetiger Posted July 17, 2007 Share Posted July 17, 2007 The front O2 sensor is bad. this explains why it only happens after the engine is warm. that when the car is in closed loop operation. The case dowes not use O2 reading during warmup and druing full throttle. only at idle and during part throttle. the sensor is giving bad readings so the the ecu cant adjust the fuel mixture properly. Spark plugs and new injectors wont fix this issue. The ECU is not thowing an O2 sensor code becuase it thinks the readings the sensor is giving is correct. Ive seen this before. Change the front O2 sensor. Link to comment Share on other sites More sharing options...
outahere Posted July 17, 2007 Share Posted July 17, 2007 Every dealer now has the Subaru Select Monitor 3 (SSM3), if you are having what feels like a misfire while driving have them test drive the car while monitoring cylinder roughness with the SSM3, the cylinders that shows roughness is the one with the bad injectors. Many dealerships just don't realize how easy the SSM3 can make their jobs and don't bother to get trained on it. Does the roughness monitor operate at idle speed? SOA customer services has already informed me that if the CEL is unlit, then there is a 99% probability of NO misfire problem. Doesn't SOA make it mandatory that their techs get trained on the SSM3? Link to comment Share on other sites More sharing options...
whitetiger Posted July 17, 2007 Share Posted July 17, 2007 The front O2 sensor is bad. this explains why it only happens after the engine is warm. that when the car is in closed loop operation. The case dowes not use O2 reading during warmup and druing full throttle. only at idle and during part throttle. the sensor is giving bad readings so the the ecu cant adjust the fuel mixture properly. Spark plugs and new injectors wont fix this issue. The ECU is not thowing an O2 sensor code becuase it thinks the readings the sensor is giving is correct. Ive seen this before. Change the front O2 sensor. Link to comment Share on other sites More sharing options...
05LGTLtd Posted July 17, 2007 Share Posted July 17, 2007 I noticed a while back that my idle didn't seem as smooth as when the car was new. I had 28K on my 05 when I put my AP in to action for stage I. I never thought I had a studder before the turbo kicked in, because I had learned to adapt with clutch and acceleration rates, I guess. I am now fairly certain I do not have a studder, with the AP running cobb stage I map. I *think* the idle feels a bit better now as well. Would the AP cancel out the incorrect readings from a faulty O2 sensor??? All I need now is a hill holder and a center passing light... Link to comment Share on other sites More sharing options...
GTTuner Posted July 18, 2007 Share Posted July 18, 2007 I would get the car to misfire, then pull each electrical plug on the injector one at a time. The one with least change in idle/misfire would be your culprit. Sounds like an injector could be the cause. Funny it's not picking the misfire in the PCM. There are certain conditions when the misfire monitor will be disabled, for instance, it will disable misfire monitor when the low fuel light comes on. I would research the enabling conditions for misfire monitor. Link to comment Share on other sites More sharing options...
whitetiger Posted July 18, 2007 Share Posted July 18, 2007 I noticed a while back that my idle didn't seem as smooth as when the car was new. I had 28K on my 05 when I put my AP in to action for stage I. I never thought I had a studder before the turbo kicked in, because I had learned to adapt with clutch and acceleration rates, I guess. I am now fairly certain I do not have a studder, with the AP running cobb stage I map. I *think* the idle feels a bit better now as well. Would the AP cancel out the incorrect readings from a faulty O2 sensor??? No. not at all. it only cancels out the rear O2 sensor used to measure cat efficiancy. the front O2 is used by the ECU to directly tune the engine's AFR. Bad readings from that O2 sensor will cause all kinds of bad things to happen including misfires in all cyliders. if you are gonna start changing parts blindly Like injectors or plugs with out a proper diag with an SSM3, The up stream O2 should be the first thing to be changed. Only after the sensor is changed should you worry about injectors or spark plugs. Link to comment Share on other sites More sharing options...
BlackMagicGT Posted July 20, 2007 Share Posted July 20, 2007 I know this misfire seems to be a fairly common experience around the LGT community and now I've joined that list... I'm going to do some basic diagnosing, and I've been trying to find the numbering of the cylinders somewhere on the forum. This thread seemed to be the best to post in... So can someone help me out with the cylinder numbers (i.e. what number is associated with each cylinder)? Thanks. Oh and sorry for jacking the thread... Link to comment Share on other sites More sharing options...
Big Mac Posted July 20, 2007 Share Posted July 20, 2007 I just brought the wagon in yesterday because of a P0303 CEL - Misfire in Cylinder 3. I got the error about 4 days ago and cleared the CEL to see if it would come back. It never did, so I was very worried that they would say nothing was wrong and my warranty expires today. The idle was rough and they were able to monitor it and got a rough idle for cylinder 2 and 3. They only had one injector in stock and swapped out cylinder 3, but I have to wait for the next injector because they are on back order. I couldn't be happier with the service I got from the dealer. Link to comment Share on other sites More sharing options...
outahere Posted July 20, 2007 Share Posted July 20, 2007 ......So can someone help me out with the cylinder numbers (i.e. what number is associated with each cylinder)?......... If you are standing at the front of the car, and facing the engine: Left front is #1 Left rear is #3 Right front is #2 Right rear is #4 Link to comment Share on other sites More sharing options...
outahere Posted August 1, 2007 Share Posted August 1, 2007 ......... if you are gonna start changing parts blindly Like injectors or plugs with out a proper diag with an SSM3, The up stream O2 should be the first thing to be changed. Only after the sensor is changed should you worry about injectors or spark plugs. I changed plugs first, mostly to see if the old plugs looked abnormal. This did not cure my misfire. Installing a new #2 injector cured the warmup misfire at idle, but not the hot idle misfire. Installing 3 new injectors at the remaining positions cured my hot idle misfire. Standing next to the tailpipes, I could no longer hear the telltale "pop pop pop" of a misfire. But the idle still felt (seat of the pants) a little rough, and so I replaced the front O2 sensor. It had no effect on idle quality. Link to comment Share on other sites More sharing options...
BlackMagicGT Posted August 1, 2007 Share Posted August 1, 2007 Can anyone provide a little basic guidance on the front 02 sensor's location, and how to swap out the injectors? And in comparison, how hard would the above pieces be to swap vs. spark plug swap? Link to comment Share on other sites More sharing options...
BlackMagicGT Posted August 2, 2007 Share Posted August 2, 2007 ^^anyone? i've already searched through other threads and no luck Link to comment Share on other sites More sharing options...
qikslvr Posted August 2, 2007 Share Posted August 2, 2007 I can help with the front O2 sensor. It is located on the passenger side about a foot back from the bumper. It is just inside the engine compartment from the passenger side tire. Jack the front of the car up using a floor jack just to the rear of the passenger side front tire. If you feel or look under the car at the front of the pass. door right where the door and fender meet; there is a round black pad where the jack goes. You will then need to take the skid plate off the engine. Again, look straight back from the pass side fog light and you will see a yellow wire going into the O2 sensor. You will also need to take the heatshield off the header/up-pipe union to access the O2 sensor for removal. It's in there pretty tight and will require an O2 socket. You could probably get it out with a box end wrench, but you stand a good chance of rounding out the nut that holds it in. From what I have read in the OE manual about the injectors they aren't so easy to get to. Maybe someone else has a better approach and will share their method. Good Luck! Let's kick this pig! Link to comment Share on other sites More sharing options...
outahere Posted August 2, 2007 Share Posted August 2, 2007 ...... You will then need to take the skid plate off the engine. Again, look straight back from the pass side fog light and you will see a yellow wire going into the O2 sensor. You will also need to take the heatshield off the header/up-pipe union to access the O2 sensor for removal. .... On my 2005 wagon, it was not necessary to remove the heat shield. It had a access hole big enough for the sensor socket. And it was only necessary to drop one side of the engine undertray to get access to the sensor. Link to comment Share on other sites More sharing options...
outahere Posted August 2, 2007 Share Posted August 2, 2007 Can anyone provide a little basic guidance on the front 02 sensor's location, and how to swap out the injectors? And in comparison, how hard would the above pieces be to swap vs. spark plug swap? Relative level of difficulty: O2 sensor install: 1 Injector install: 4 Spark plug install: 6 Injector removal on the drivers side is straightforward. On the passenger side, remove the short intake tube, and the upper coolant tank, to get easier access to the injectors. To remove the injectors, twist and pull. I had to use pliers, because I don't have bionic fingers. Link to comment Share on other sites More sharing options...
BlackMagicGT Posted August 2, 2007 Share Posted August 2, 2007 ^^thanks a ton guys, I'm gonna go fool around now and see if can't make the misfires even worse, ugh...I'm really not a noob, I just haven't worked much with the fuel/emissions systems other than the spark plugs. I'm assuming then the rear O2 sensor is the one just prior to the turbo? Link to comment Share on other sites More sharing options...
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