why why why is my passat so greedy :(

[ihpassat]

Guys really love my passat to bit it's 1.8 apt, but i feel it's really greedy on fuel half a tank normally get me about 100miles if am lucky and on the computer it says around 23mpg-26mpg on normal road and on m way around 32mpg if am lucky! but to be honest i don't know if it's telling the truth! i know it's not mega powerful but why is it so heavy on fuel

So far i've got an iduction kit and 18'' rims and thats all the mods i've done! really don't want to give the passat up cause i've spent ££££ on it the last year or 2 on new clutch and flywheel and new cylinderhead and gasket etc list goes on.

also checked if there is any holes or leaks on each pipes and everything seems fine!!