If you look at the throttle cable and the linkage, there is a small grey switch. This is the deceleration micro switch or throttle position switch. There is a small rubber boot under the switch. Check it. On mine the boot was ripped. I replaced this switch, u need a 7 mm wrench, and now the car idles rock solid. With the a/c turned on, it is also rock solid. The switch runs about 25 bucks. Good Luck, Joe