dr_sharp Posted February 21, 2011 Share Posted February 21, 2011 I think we've all had this at one time or another and I also think that 90% of the time it has to do with intake piping or MAF. Now, I've had a rough idle since just before I was tuned. My tuner increased the idle rpm to help eliminate stalling and he also added something where the car 'catches' itself before a stall and adds throttle. I have a list of items to check out - in order from highest of likelihood to lowest: Bad O2 sensor Spark Plugs Intake Leak or leaky BPV Bad water or power steering pump Bad injectors Coolant temp sensor Cams/timing/valves I was tuned with the rough idle and still made power, further reducing the likelihood of intake leak. Any additional thoughts would be greatly appreciated. lol Link to comment Share on other sites More sharing options...
GTTuner Posted February 21, 2011 Share Posted February 21, 2011 Are you using more oil than usual? Intake leaks can be looked at by monitoring LTFT and STFT when the car goes into closed loop. Spray carb cleaner around pre and post MAF areas and watch for any sudden change. Cylinder leakage is an issue with these motors, the local dealer is finding lots of crappy valve seats not sealing and burning valves. What are you using for plugs? Link to comment Share on other sites More sharing options...
dr_sharp Posted February 21, 2011 Author Share Posted February 21, 2011 stock plugs. and yea, carb cleaner is my next step. lol Link to comment Share on other sites More sharing options...
sirbOOm Posted February 22, 2011 Share Posted February 22, 2011 My idle cleared up a lot after new plugs. Then it cleared up a little more after my steering rack was replaced - not sure why. It still isn't a perfect idle (i.e., consistent vibration all the time) - it seems to cough every so often to the point where I'm not worried about it as every Legacy I've been in (3) idles in the same way. Link to comment Share on other sites More sharing options...
dr_sharp Posted February 22, 2011 Author Share Posted February 22, 2011 Thanks for the info. Did you replace stock plugs with stock plugs? lol Link to comment Share on other sites More sharing options...
sirbOOm Posted February 22, 2011 Share Posted February 22, 2011 Yep... the OEM NGK Iridium plugs bought off of Amazon.com for the best price. Consensus seems to be that these are the only plugs you should be using - don't use copper or fancy variations with split tips and all that stuff. I'm no performance tuner or mechanic, but the OEM plugs are pretty high end compared to what comes in other cars - which probably has something to do with needing 93-octane. Anyway, took me upwards of 3-hours to do it because I had to rig up some tools to get down in there. The idle smoothed out considerably. I changed them at about 65K after I realized that the 60K service didn't include new plugs. Seemed ridiculous to me considering a major part of a tune-up is, indeed, replacing the spark plugs. Bygones... I had to have my steering rack replaced because it was leaking internally and would whine when I started up the car in cold weather. I thought it was the turbo, but the turbo is fine. I figure maybe the rack wasn't allowing the belts to rotate smoothly causing some frustration in the idle. I haven't felt any idle cough much since and it seems to have gotten better over the week or so that I've had the car back from the shop. Could be imagining that but I'll take it. Link to comment Share on other sites More sharing options...
dr_sharp Posted February 22, 2011 Author Share Posted February 22, 2011 Thank you for all of the info, will definitely mention my concerns - and your experiences - to my dealer. lol Link to comment Share on other sites More sharing options...
ouch1011 Posted February 22, 2011 Share Posted February 22, 2011 My reading has shown that plugs are due at 60K. At least in the literature I read. Link to comment Share on other sites More sharing options...
wpgspecb Posted February 28, 2011 Share Posted February 28, 2011 Yep... the OEM NGK Iridium plugs bought off of Amazon.com for the best price. Consensus seems to be that these are the only plugs you should be using - don't use copper or fancy variations with split tips and all that stuff. I'm no performance tuner or mechanic, but the OEM plugs are pretty high end compared to what comes in other cars - which probably has something to do with needing 93-octane. Anyway, took me upwards of 3-hours to do it because I had to rig up some tools to get down in there. The idle smoothed out considerably. I changed them at about 65K after I realized that the 60K service didn't include new plugs. Seemed ridiculous to me considering a major part of a tune-up is, indeed, replacing the spark plugs. Bygones... I had to have my steering rack replaced because it was leaking internally and would whine when I started up the car in cold weather. I thought it was the turbo, but the turbo is fine. I figure maybe the rack wasn't allowing the belts to rotate smoothly causing some frustration in the idle. I haven't felt any idle cough much since and it seems to have gotten better over the week or so that I've had the car back from the shop. Could be imagining that but I'll take it. edit: nm Link to comment Share on other sites More sharing options...
datrumole Posted March 16, 2011 Share Posted March 16, 2011 O2 sensor buddy....O2.... Link to comment Share on other sites More sharing options...
LosAngelesLGT Posted March 16, 2011 Share Posted March 16, 2011 only if the afr are going a little wonky. post a learning view or log Marshalito Link to comment Share on other sites More sharing options...
dr_sharp Posted March 16, 2011 Author Share Posted March 16, 2011 Don't have access to logs but will immediately rule out O2... my tuner uses a wideband during tuning and would've seen a bad O2 if it were true. lol Link to comment Share on other sites More sharing options...
dr_sharp Posted April 28, 2011 Author Share Posted April 28, 2011 O2 sensor buddy....O2.... After a bit more reading, I am going to try the upstream. I just picked it up from Autozone today. Hopefully I'll get some time during the next weekend or two. lol Link to comment Share on other sites More sharing options...
e_NiNo Posted May 3, 2011 Share Posted May 3, 2011 and ? some new ? I have the same trouble Link to comment Share on other sites More sharing options...
babybluelgt Posted May 4, 2011 Share Posted May 4, 2011 any check engine lights? Link to comment Share on other sites More sharing options...
dr_sharp Posted May 4, 2011 Author Share Posted May 4, 2011 No CELs for me. Still haven't had an opportunity to install the new one. lol Link to comment Share on other sites More sharing options...
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