I'm driving a 230E w124 benz... previously my fuel comsumption is about 340 for a fuel tank.. but 2 weeks ago my alternator failed n was replace.. after that.. my fuel comsumption has worsen badly to 120km on a full tank.. i'm hoping some one here could help think of the cause and what should i do.. i'm desprate man.. its killing me.. my mechanic say he will retune the car n see what happens.. any other things i should look into?