Just got a Civic 05 Exi prosmatec from a friend with 44,000 kms done, the owner got CNG out , I`ve got it tuned by KHAN but still the petrol mileage is extremely bad, i guess around 5 km/litre. The guys at Khan could not find any problem with anything. Any suggestions .. what might be causing such bad fuel consumption . has it got anything to do with the taking out of the CNG ?