CHUGGING IN 2000 S6???

[daphantom]

My 2000 S6 just doesnt run smooth in automatic but seems to be ok in tiptronic??? what could the problem be? spark plugs?? gear box fluid??? - ive only had it a week and it just isnt running as well as it should yet its just had its major service -belts etc so if no-one has any suggestions i'll just have to leave in to a dealers

thanks