I have a 2009 Legacy 3.0R with 103k miles on the clock, have owned it since 45k miles and its been a great car. Recently I have been having some weird check engine light issues that scan to bank 2 misfires on all three cylinders, the car still runs completely normal and does not feel down on power at all. After disconnecting the battery it did have some issues with idle mainly when coming to a stop at a red light the RPM's would dip down to around 400 and it would feel like it was going to stall but never would. Also if I reved the car the RPM's would climb normally but fall really fast and again dip to around 400 and after a second bounce back up to a normal idle. After driving for around 75 miles it has since seemed to relearn and is no longer an issue. Just put brand new OEM plugs in the car as well.
For the past few months pretty much at complete random I would have times where the CEL would flash for around 3-5 secs while driving then shut off and return to normal. It has now been staying on not flashing, car still runs just fine. The codes I am getting are:
P0306 cylinder 6 misfire
P0304 cylinder 4 misfire
P0302 cylinder 2 misfire
20B12 preparatory code
20B02 preparatory code
We also read the MAF and MAP sensors and they seemed to be reading steady and responding correctly. Looking at the values for the A/F Learning and Correction for banks 1&2 we thought these values might be a good bit high. Because of this and the idle relearning issues I think I have an idea of what the issue is but wanted to get some opinions before throwing parts at it. Thanks!
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