We recently had the fast idle stop working for no apparent reason and I finally got back to investigating it after completing the bedroom re do. As Gil mentioned relay 7 (in our case on the old XL, r 77) is where to start looking. According to the electrical drwgs relay 77 is in the fast idle circuit but it was not found in the front or aft junction box leaving me scratching. Eventually I located it under the dash right side in our case, seems like there ar many configurations. Swapped it out and fast idle works perfectly. Another step up the learning/confidence curve accomplished. Thanks again to those responding and helping out others.