WordNet (r) 3.0 (2006):

go through the motions
    v 1: pretend to do something by acting as if one was really
         doing it; "She isn't really working--she's just going
         through the motions"

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "go through the motions":
   act, act a part, affect, assume, bluff, counterfeit, cover up,
   dissemble, dissimulate, fake, feign, four-flush, gammon, let on,
   let on like, make a pretense, make as if, make believe, make like,
   play, play a part, play possum, playact, pretend, profess, put on,
   sham, simulate