To determine the causes of this malfunction, special diagnostic equipment is required, therefore, in this case, we advise you to contact a service station that specializes in repairing cars with injection engines.
However, it should be noted that most often this malfunction is caused by a failure of the idle speed controller or by the suction of foreign air through loose hose connections connected to the intake pipe. If replacing the regulator (see «Supply system») and tightening the hose clamps to restore idling failed, contact a specialist.