I had my crank pulley replaced and now my van runs hard and i hear a knocking

You should contact the facility that did the work so they can advise you upon what to do. It is recommended to refrain from operating the vehicle / engine until *hands-on* visual inspection / evaluation can be performed by qualified personnel - otherwise damage to engine or other components may result. Some-thing is amiss - however we can’t advise further here online. Good luck!