Salam,
I have been noticing a strange problem in City 2001 exis. The RPM jumps to 2000 when the car is in idle with AC running, however as soon as I switch off the AC the RPM comes back to 1000. This happens after driving the car for about 15-20 kms During the 15-20 kms journey, the RPM remains normal whenever car stops at signals etc.
The cooling of AC is fine but thermostat is faulty, i.e the AC does not trip itself, has to be manually switched off. I don't know whether this problem relates to some engine issue or there is an issue with the AC servicing etc.