Vibration at Idle

The car vibrates all over at Idle when I am at stop in a traffic with the gear in drive or reverse. It is more when the air-conditioner is ON and sometimes there is this short stumbling vibration like a shock-feel as the air-conditioner thermostat kicks ON and OFF which makes the rpm needle surge as if it will stall. Idling speed is between 650-700 rpm. I have changed the A/F ratio sensors B1S1, oxygen sensor B1S2, all 4 ignition coils, intake manifold, spark plugs, thermostat, air filter, cleaned egr valve, injector nozzles, throttle body, and MAF sensor. Still no improvement. My mechanic has checked all engine mounts and they are all ok. The vibration tends to reduce a little when I switch to neutral or park but it could still be felt on the steering, slightly. Car hesitates too.