I bought Toyota Passo 2012, 6 months ago, with 80k on ODO. The car was running about 139-140 kms a day with fuel avg of about 14-16 km/ltr in Karachi city. However, suddenly the avg dropped to 6-7 km/ltr in city, but goes up to 14-15 on highway. Mechanic suggested to get Catalytic converter checked for any cracks and get it cleaned if its in fine shape. However, It didn't solve my problem. I got throttle body cleaned, spark plugs checked, Oils checked, filters checked, oxygen sensor checked and cleaned. Everything seems to be fine. But the problem remains. I need serious advice from experienced fellows out there