i have found the ford technical bullitain but it is for later ka's than yours(96 on) and it is for "idle speed hang up during gear change" which in laymans teams means engine revs uncontrollable during gear changes.
and it recomends fitting a modified throttle position sensor multi plug, finis code 1 150 138.

i can scan the sheet and post it up here if you want as it explaines how to do the job.

cheeRS nick.