ecky Posted January 27, 2009 Share Posted January 27, 2009 On 08/08/08 I put myself in debt for the first time. I bought an '05 forester XT with 58,000 miles. It now has about 70,000 miles and is idling ruff. I took it in and had it's 60K done on time hoping it would go away, but it hasn't. On another note, I hear a whining noise coming from the auto trans. when shifted into drive. Just kinda wondering if these are common issues, or something to worry about. We also have an '05 legacy with the auto trans. and I haven't noticed either of these issues with it. Quote Link to comment Share on other sites More sharing options...
OB99W Posted January 28, 2009 Share Posted January 28, 2009 Details might help with a diagnosis. Is the idle rough just when cold, just when warm, all the time, etc.? Exactly what was done/replaced at 60k? Some links to possibly useful info: http://endwrench.com/images/pdfs/LegacyIdleSum04.pdf http://www.endwrench.com/pdf/fuel/FtEmissionServiceS01.pdf Quote Link to comment Share on other sites More sharing options...
ecky Posted January 28, 2009 Author Share Posted January 28, 2009 It only runs rough when it is fully warmed up. Anything above idle is smooth hot or cold. It's not throwing any codes and I just double checked and made sure that #1 injector is fireing. When watching the tach, I can see the needle float ever so slightly at idle. All filters ( fuel, oil, air, trans,), spark plugs, belts. (but not the timming belt.) and fluids were changed at 60k. It feels like a miss to me (bounces the whole car). But again no codes, and the idle air control valve has not shut off the #1 injector. If their is anymore info I can give let me know. I'm just getting really annoyed with the bouncing at red lights. And thanks very much for the links. Quote Link to comment Share on other sites More sharing options...
bheinen74 Posted January 28, 2009 Share Posted January 28, 2009 ecky ecky ecky.what brand plug wire, and sparkplugs did you use? hopefully NGK and subaru's oem wires, not some aftermarket garbage. .also, is it a K&N filter, the oil on them messes up the MAF terribly so. Quote Link to comment Share on other sites More sharing options...
OB99W Posted January 28, 2009 Share Posted January 28, 2009 If the ignition is in good shape, then a floating idle speed usually points to mixture problems. The engine runs open-loop when cold, defaulting to a rather rich mixture, which can disguise certain things. Once it warms up and the ECU can read oxygen sensor data, it should go to closed-loop operation, and be leaner-running. Besides the things that bheinen74 mentioned, a front oxygen sensor that's misbehaving can sometimes cause the problem, as can something as simple as a dirty PCV system; often neither will cause a code to be set. Gas mileage can be a rough indicator of whether the mixture is wrong -- what are you getting? Quote Link to comment Share on other sites More sharing options...
OB99W Posted January 28, 2009 Share Posted January 28, 2009 (edited) Ooops, almost forgot to mention a possibly dirty IACV, and to check for any vacuum leaks. Edited January 28, 2009 by OB99W Quote Link to comment Share on other sites More sharing options...
ecky Posted January 29, 2009 Author Share Posted January 29, 2009 It has factory spark plugs (NGK is all I run) and the air filter is (newer) stock. I don't believe that it has spark plug wires. It looks to me like it has those coil-pack thingies like the SVX's do. I'll spend more time tomarrow and check vac lines and emission valves. I'll clean the MAF with MAF sensor cleaner and see if that helps. I figured the MPG yesterday and it was 19.3. I'll also price an O2 sensor and if reasonable replace it and se if that works. Again thanks guys. Quote Link to comment Share on other sites More sharing options...
OB99W Posted January 29, 2009 Share Posted January 29, 2009 [...] I figured the MPG yesterday and it was 19.3. Depending on your driving style and other factors, 19.3 MPG might be on the low side. Do you have access to a scan tool (not just a code reader)? If so, the LTFT (Long Term Fuel Trim) and STFT (Short Term Fuel Trim) (especially idling for a while with engine warm) numbers and sign (+/-) could determine if the ECU is correcting for an A/F-related defect, and help point in what direction to go. I'll also price an O2 sensor and if reasonable replace it and se if that works. I'd suggest only considering an OEM (Subaru) front O2 sensor, which might be reasonable if purchased at discount from an online supplier. Of course, check the less expensive stuff first. Quote Link to comment Share on other sites More sharing options...
ecky Posted January 29, 2009 Author Share Posted January 29, 2009 Cleaned the MAF sensor and checked everything again. No luck. Everything else is fine, and seems normal. I'll just let it go for now. I wannna thank you all for your suggestions, but I've been dealing with it for months now and untill it throws me some codes I guess I'll continue to ignore it. Again thank you and I'm still open to suggestions. Quote Link to comment Share on other sites More sharing options...
OB99W Posted January 29, 2009 Share Posted January 29, 2009 You're welcome -- hope you pin it down some day. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.