Dear Amir Ansari,
I have Suzuki Margalla (1996) 1300 cc from last 10 years. Its fuel average is good at long routes but not very good in city (karachi). last year i went Kund Malir where I got 15-16 km / Liter without AC. And in city, I usually get only 8-9 km-liter without AC.
but the most important thing is that i usually drive slow with very low acceleration & low rpm. Plus the Carburetor of your car should be new, kabuli or in good Condition,,, Butter fly should be properly repaired,,,, Air Filter should be new of cleaned,,, Spark plugs should be new or cleaned,,, All the tyres should be well alligned after every 6 months.