96 leSabre 3.8 High Idle

I have a 96 LeSabre with a 3.8 and have been battling a HIGH idle problem. The engine idle continues to rise for no reason. Starts at 1200 and works its way up to 3k + rpm for no apparent reason. I replaced the throttle position sensor, coolant sensor ,cleaned the throttle body . Then I tried disconnecting the throttle position sensor and the idle went down. Connect it and it starts going up. Now today I strted it and left if disconnected and the idle went up. I reconnected it and it came down. I am totally bewildered at this point .. Any suggestions ????? Oh by the way I thought maybe I had a vacuum leak somewhere but I can't find any.....

There is an idle air sensor that may be defective.