the carburetor in my corolla xe was replaced last May 2013 with a new one, however, my fuel economy has dropped to around 7 km/l whereas it was still doing around 10 km/l before my original carb gave out when my car was a submerged when ondoy hit... it was initially replaced with a 5k carb, my mechanic adjusted the timing to around 11 or 12 degrees to compensate. i'm wondering if i should return to engine timing to 10 (as per spec), so that my engine can function optimally... the air-fuel mixture right now is ok... i hope to have the car return to around 8 or 9 km/l... any thoughts?