Hi, I'm driving Chevrolet Optra, having A/C problem. When start driving, it is okay but after somewhile, the smelly gas will come out (sour smell), when I push the button for the outside air to come in, it will be fine but put it in the indoor air, the smell will be coming back. Furthermore, if driving for long, suddenly the air flow will become very weak, even when I tune to the highest speed, the airflow still very weak and the fan is very noisy.

Based on your experience, why this happenning, I just change my air filter about 2 months ago, the problem still there.

Please recommend a gd workshop near kajang and give me a rough idea on the cost.