I have been driving a 2002 Outback Legacy with the CEL steady for longer than I would like to admit. Manual transmission has always been difficult to shift smoothly since I bought it used. I attributed this to soft motor mounts which allowed the engine to lunge when clutch is engaged, and occasionally the clutch shudders. Whiplash is common in gridlock traffic. Lots of people are at wit's end with Subaru and their lame excuses, such as, you must have damaged your car by racing it (esp WRX's) I have read tons of complaints about clutch shudder, and clutches wearing out early on line, but few solutions. On a lark, I read up on the knock sensor, and found that some folks are complaining about "hesitation" with knock sensor problems. I had an appointment to get my code read and an emissions inspection done, but was not looking forward to getting raped by the service department of the local repair shop. On advice of some do-it-yourself info online, I reset the computer by disconnecting the battery for several minutes and holding brake for 30 seconds, then relocated the knock sensor to another hole further from the crankcase. Voila! No more light, no more shudder and stalling and whiplash. She drives just like any other car now! I imagine the shop would have sold me a new knock sensor, and I would still have the same problem $300 later.