Ruhlman Posted October 9, 2013 Share Posted October 9, 2013 Hi Everyone. New to the forum here so I apologize in advance for my potential bad forum manors. Here is the deal. I have a 2005 Legacy GT with 106K miles on it. Just recently completed 105 service with subaru parts (belts, plugs, water pump, etc) Before taking the vehicle in for service I did not notice any misfiring, rough idle or other issues with the vehicle. The car pulled like a champ. Now, post service I immediately noticed a light sputter or rumble when on boost and a few minutes later the CEL came on and I pulled P0303. We swapped coils, cleared codes, but a few miles later CEL came on and another P0303. So I know this is telling me a have a misfire in cylinder 3. The car still idles normal. I only notice the problem when accelerating. Still pretty good boost being attained. My question is has anyone had experience with resolving this issue? It seems like a common occurrence from what I have read, but people have hard time resolving it. Another question is why would car be fine before service and instantly have an issue after service? Just looking for guidance and what I may have to possibly prepare myself for in terms of repair/cost. We will start with compression test tonight, and was going to run some fuel injector cleaner through it. **Possible important info - I replaced clutch and flywheel at 85K. Service guy talked me into light weight flywheel kit. CEL codes have shown intermittent P0420, P0335, P0340 codes in the past, but we couldnt figure out the cause. Not sure if that is important to know or not for diagnosis. At the moment of this post I am only showing P0303 and P0420. Other than clutch and flywheel the car is bone stock. I use premium gas every time I fill up and change oil every 5K with full synthetic 5w-30. I drive "spiritedly" but am not beating the car up. Thanks for your help. Link to comment Share on other sites More sharing options...
rob-2 Posted October 9, 2013 Share Posted October 9, 2013 Have you moved the injectors around to see if it follows an injector? Link to comment Share on other sites More sharing options...
ehsnils Posted October 9, 2013 Share Posted October 9, 2013 Intake manifold leaks at a gasket or a bad hose causing the cylinder to run lean is my first suspicion. Fits with the age of the car if the compression test checks out. A second cause can be a too tight valve clearance. Compression may check out at cold engine but valve may fail to close at hot engine causing misfire. At that distance the injectors can also be culprits - and if the service was including running injector cleaner it may very well result in the opposite - clogging of an injector. But there's only a few dollars to lose running more injection cleaner compared to remove the injectors and run them through a true cleaning and make sure they are matched. The 420 code at that distance is either the cat or an O2 sensor, running a log session should be able to show more. Of course - a bad O2 sensor can cause misfires, but a bad cat usually don't - it just results in more exhaust smell. If the cat is bad enough you shall be able to smell the exhaust fumes after the car has been driven a few miles and you stop with engine idling. But the cat may have been detected as bad before that. Now I have probably added to your confusion! Link to comment Share on other sites More sharing options...
SCASEYS Posted October 9, 2013 Share Posted October 9, 2013 fix your 420 code 1st resistor pill fix you still have the stock up pipe? I donated to LegacyGT.com which allows me to have this nifty signature. If anything SCASEYS posts ever becomes a sticky i'm gonna light this whole place on fire Link to comment Share on other sites More sharing options...
Ruhlman Posted October 16, 2013 Author Share Posted October 16, 2013 Alright so the car has been to the dealer to perform compression test to determine the reason of the p0303. Results of compression test were within spec. Cylinder 1 - 152psi, cylinder 3 - 145psi. They did not provide/or run tests on 2/4 However I failed the leakdown test in cylinder 3 at 15% and spec is less than 10%. Couple of questions. I have heard that possibly this engine has the type of valves that can be "shimmed" to reseat the valve. Does anyone have experience with this or know if this 2005 model has those type of valves? This was recommended from Subaru mechanics in Indiana that said it could be a possibility before tear down and sending it out. Other than this option, which the my local dealer did not bring to the table. They are recommending complete disassembly and sending valves and heads to be repaired for $3749 p/tax. Thoughts, concerns, options? Should I look at short block rebuild or would I be spending the same? Gaining anything by doing that? Forgive me, my knowledge is not that extensive. Thanks. Link to comment Share on other sites More sharing options...
JmP6889928 Posted October 16, 2013 Share Posted October 16, 2013 Before spending that money, I would remove the coils and twist the pins slightly inside of the coils where the loom plugs snap into place. I've found that they can become loose and cause misfire. If you twist them slightly with a pair of needlenose pliers, it will give better contact. Once you twist them, a tiny bit of dielectric on the female plugs and snap them back into place and see if it takes away the misfire. You had the service 1K ago, and now are having misfire. That's why I would suspect that the coils are not making good contact. Another issue that can happen is that possibly they cracked one of the plugs when installing and it can cause all kinds of issues. If the twist pins method does not help, remove that plug and inspect it closely and see if it is cracked. Good luck. Link to comment Share on other sites More sharing options...
Gex Posted October 16, 2013 Share Posted October 16, 2013 +1 for a coil issue. They are extremely fragile. I keep a spare on hand in the parts bin. Link to comment Share on other sites More sharing options...
JmP6889928 Posted October 16, 2013 Share Posted October 16, 2013 +1 for a coil issue. They are extremely fragile. I keep a spare on hand in the parts bin. I actually have 2 for track days....LOL Link to comment Share on other sites More sharing options...
Ruhlman Posted October 18, 2013 Author Share Posted October 18, 2013 coils have been swapped and plugs checked. The dealership confirmed leaking valve. This morning was a doozy. No check engine light this morning. Drive 5 miles and it comes back on. Check the codes. P0420, p0335, p0102, and p0113, NO P0303!! I know what the codes mean but why did the p0303 go away? Why all of the sudden am I having MAF sensor misreadings? Air intake Temp issues? Could the dealership have missed re connecting wires after compression and leak down test? Car runs as normal, seems like everyone else who has a crankshaft misreading has idle or drivability issues. Link to comment Share on other sites More sharing options...
JmP6889928 Posted October 18, 2013 Share Posted October 18, 2013 coils have been swapped and plugs checked. The dealership confirmed leaking valve. This morning was a doozy. No check engine light this morning. Drive 5 miles and it comes back on. Check the codes. P0420, p0335, p0102, and p0113, NO P0303!! I know what the codes mean but why did the p0303 go away? Why all of the sudden am I having MAF sensor misreadings? Air intake Temp issues? Could the dealership have missed re connecting wires after compression and leak down test? Car runs as normal, seems like everyone else who has a crankshaft misreading has idle or drivability issues. Disconnect negative battery cable for about half an hour and also hit brake pedal slowly several times while it's disconnected. This will clear all of the codes and reset the ECM. At the same time, remove MAF and clean it GENTLY and make sure the o-ring is sealing it to the housing. Put a tiny bit of dielectric on the o-ring to make sure it slides smoothly into the hole before tightening the screws. Make sure the connector is completely snapped into place and look at every single connector that your list of codes implicate and make sure they are all snapped into place firmly. Re-connect battery cable and then turn ignition on, wait for gauges to cycle so fuel pump can prime, and start it. Drive it slowly around your neighborhood and see if the codes re-set. If not, then take it onto faster roads and let the ECM re-learn itself. Sometimes clearing codes with OBDII scanner or AP, isn't enough. The reset of the ECM may solve all of your problems. The issue here is that your car ran fine BEFORE the service, and NOW it doesn't run fine. The issues HAVE to have come from the service that was performed. Really look closely at the list of things you had done and begin with that and make sure that everything is correct. If any parts were changed, make sure WHAT they were, the manufacturer of the parts, and go to their website and check the part numbers you have listed. It happens sometimes that repair facilities put the wrong damn parts on and it can screw everything up. Good luck. Link to comment Share on other sites More sharing options...
ehsnils Posted October 18, 2013 Share Posted October 18, 2013 coils have been swapped and plugs checked. The dealership confirmed leaking valve. Can be as simple as need for a valve clearance adjustment. Start with that - and check with a workshop that does that unless you can do it yourself. Link to comment Share on other sites More sharing options...
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