The excessive high idle speed after warm up in gear of 800-850 rpm is excessive. this high idle speed makes controlling the car in stop and go traffic difficult due to the high brake pedal pressure to keep the car from moving. the most difficult circumstance was having three tires on ice and one on dry pavement. the quattro drive transferred all the power to the one tire that had traction. i was unable to hold the car and bumped the car in front of me. no damage. the car has been in to the dealer twice to have this corrected and i have been informed that since model year 2008 the idle speed is not adjustable.