What is the most common cause not to drop to normal idle speed on a warm engine (XUD9TE)? It keeps on running on fast idle, even with hot engine, with or without airco switched on.
Things I checked: Vacuum hoses - OK Temp sensors (3 in total in the thermostat housing) - OK Diaphragm and cable - OK Idle and fast idle setting screws - OK
BTW, the airco only works on revs higher than idle. Do these two things have a link? Thanks.