it looks like i'm lossing about 100 miles out of a full tank of gas on 2005 Hyundai Sonata

i just got a new belt, water pump and changed the spark plugs

Asked by for the 2005 Hyundai Sonata
no codes or check engine light? maybe you have evap system problem or as simple as put a new gas cap
no check engine light,,,, new gas cap???? i also just got a new fuel pump with the other parts