Where is the IAC valve located? My 87 2.5l sedan's idle starts surging when the outside air temperature falls below 40 degrees. Warm weather no problem, but as soon as it gets cold outside is when it acts up. Once the car gets to operating temperature it usually stops but recently it will stall out when I come to a full stop. Any suggestions? The car is fully tuned up and all the air is bled from the radiator.