I had the same problem with my 87 2.1 automatic last Nov. These vehicles
are really scary to stop on ice when they are idling at 2000, the front
wheels are locked and the rear wheels are pushing.I adjusted my throttle
valve switch to make the fuel shut off when the throttle was closed
which brought the idle below 1000. In order to fix the uneven idle
swinging from 800 to 1200 I had to replace the idle stabilizer control
unit(these are known to go defective)unscrew and remove the right
taillight and you will  see it against the  bulkhead  either unscrew the
mounting bracket or unplug it from the wires or bracket to remove.

Gerry 87 westy