guyrat

Hi, I have a 1985 Toyota sprinter which used to do well on fuel. There was an oil leak and the engine was recently overhauled. now the car does a little over 8 KM per litre. It used to do over 10 per liter in town with AC. Anyone knows how this can be fixed? Last week, the Carb was cleaned with cleaner. the rings have been replaced with the spark plugs, plug harness etc. There does not seem to be a performance loss but there is a loss of mileage which is very expensive. Any hints to fix this? I was told this carburettor is complicated to tune so maybe the garage accidentally changed something that should not be changed. Thanks! Gayan