I have a 2008 Scion xD automatic that has chest over 200,000 mi on it and it will shake and idle really low but will only throw a check engine light if the AC is turned on and says bank one sensor one system lean but without the AC on it will still do the other. I have replaced the map sensor check the air filter and replace it the coil packs have been replaced as well as spark plugs PCV valve fuel pump and various other parts that I could try and figure would cause such a thing with no luck. It has been taken to three different shops plus the dealership I've had about four or five different mechanics look at it individually and no one can seem to figure out what the problem is dealership says it is completely within spec other than idling low but it feels like the car's about to shake apart whenever it does it sitting at a red light as soon as you give it throttle smooth out and purrs like a kitten. The only thing that hasn't been done that I'm considering next would be a smoke test which I was told was done but beginning the second guess and then the computer.