Lower fuel economy

I replaced the fuel pump and sending unit in my 96 Yukon. New platinum plugs, cap and rotor and fuel filter and air filter. I had the fuel injection service done and I just got the four wheel drive checked out. Cleaned throtle body and IAC. Also cleaned MAF sensor with proper cleaner. After doing all this my mileage has been reduced from a range of 725 km per 100 litres of fuel to about 450 km per 100 litres of fuel. Any one got any ideas what may have happened? Lots of power, no hesitation. Tires all up to pressure and no change in driving habits. Thanks

Your old fuel filter was plugged making the engine run lean. Therefore thats why you were getting the better mileage. The plugged filter is also why your fuel pump went bad.