Ruhlman Posted January 13, 2016 Share Posted January 13, 2016 I have a 2005 LGT manual w/ 125K miles. A little background @105K miles performed all necessary recommended service.. belts, plugs, etc. Coincidentally a misfire in cylinder 3 (P0303) began to occur. We swapped coils, tried new plugs and the issue stayed in 3. Performed compression test and turned out to be a leaking exhaust value. The fix was way more $$$ than it was worth for the cars value, so I decided to drive it as is and roll the dice that the car would last. That was over 2 years ago... Starting last week, I have the same misfire code (been a off and on constant for the whole time) but no other codes are being thrown. Sometimes it will show a blinking check engine light which it has not done until this issue. Car still idles fine, upon acceleration the car bucks, as if someone where constantly tapping and letting off the gas. Basically it feels as if power is on then off, on, off, till about 3K RPMs and then its ok until of course you need to shift into the next gear. Im sure it has something to do with the misfire, but its not constant, so I cant explain it. Its fine idling, and actually can become somewhat drivable after it has warmed up. Does anyone have an experience with these symptoms. I have seen some posts but nothing describing these exact symptoms. I have attached the live data I pulled from the ECU the last time I drove it. Maybe it can provide some answers on where to start. Thanks for your help.2005 Subaru Legacy GT Live Data.pdf Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 13, 2016 Share Posted January 13, 2016 If you have a leaky exhaust valve and keep driving on it, you will burn it and completely destroy it. I had a leaky exhaust valve in cylinder 2. I caught it on time and readjusted its clearance myself (see here: http://legacygt.com/forums/showthread.php/my-turn-adjust-valve-clearances-242071.html). It cost me my time and parts (~300$). But if you wait too long and burn the valve, then it will certainly cost more than $300. Link to comment Share on other sites More sharing options...
Ruhlman Posted January 13, 2016 Author Share Posted January 13, 2016 Would that not lead to P0420, If it was completely burned? Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 13, 2016 Share Posted January 13, 2016 I would say not necessarily. In any case, if it is not your DD, I would check the valve clearances on that side of the engine (passenger side). How is your oil consumption? Link to comment Share on other sites More sharing options...
Ruhlman Posted January 13, 2016 Author Share Posted January 13, 2016 Maybe 3/4qt over 5000 miles... Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 13, 2016 Share Posted January 13, 2016 That's not bad at all. Can you log roughness per cylinder? If yes, did you see how it behaves at idle or while driving? In a perfectly healthy engine, it should stay at 0 almost all the time. In my case when I had a leaky exhaust valve, it mostly showed up when the engine was warmed up at idle. Link to comment Share on other sites More sharing options...
Ruhlman Posted January 13, 2016 Author Share Posted January 13, 2016 I attached the live data in the first post, I pulled while driving home the another night, it was about 5 miles. Other than that I am not sure how I would log the roughness. Can you provide some details? I get some minor rough idle when sitting at traffic lights but it has done that since I bought the car at 65K miles, so Ive never thought much about it. The worst symptoms occur when on power 1.5-3K RPMS. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 13, 2016 Share Posted January 13, 2016 What are you using to read the live data? It is a bit hard to read this way. FWIW, I already had a tight valve at 55k miles.. And I can say that if the valves clearance is set up properly, and the piston rings are fine, AND you don't have any vacuum leak, your idle should be butter smooth. The symptoms you described are similar to what I was experiencing. Link to comment Share on other sites More sharing options...
Ruhlman Posted January 13, 2016 Author Share Posted January 13, 2016 Its from Harbor Freight... Dont have the model number present. Can any provide from experience a trusted subi mechanic in the phoenix area, preferably the west valley? Link to comment Share on other sites More sharing options...
AMileHighLGT Posted January 13, 2016 Share Posted January 13, 2016 #1 driving around with a cylinder #3 misfire for a long period of time is not good. or any cylinder misfiring.. burned valves that leak are common. Driving around misfiring in cylinder 3 has the potential to damage the motor internally, especially if that fuel injector keeps spraying raw fuel into the cylinder. you will fuel wash the walls, you will fuel contaminate the crankcase and potentially damage your piston rings, bearings, etc. Furthermore, if any of the unburned fuel makes it far enough into the exhaust system, you will shorten the life span of the catalytic converter... Eventually down the road it may lead to a P0420 code, but not because of a burned valve but because the catalytic converter decides to stop working after fuel poisoning. Link to comment Share on other sites More sharing options...
Max Capacity Posted January 14, 2016 Share Posted January 14, 2016 contact Geoff at http://www.full-race.com/contact-us/ Tell him I sent you, the guy from CT with the yellow Civic hatchback single cam, about 10 years ago. Geoff does great Fab work. As for the car not being worth it, most of us here will say your wrong. These cars offer great bang for the buck, if your into that kind of thing. They just need a great Tuner. Here's one of the best, http://legacygt.com/forums/showthread.php/else-loves-their-tuning-alliance-tune-246078.html 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
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