A motion for a more definite statement is available under Rule 12(e) of the Federal Rules of Civil Procedure. 

Such motions may be a useful and necessary response to unintelligible pleadings.  However, their use as a tactic to challenge pleadings generally is unlikely to be effective.  See e.g., Moore v. Fidelity Financial Services, Inc., 869 F.Supp. 557 (N.D.Ill. 1994)(denying motion).

As explained in Moore, Rule 12(e) motions are generally disfavored.  They are not to be used as substitutes for discovery. Notice pleading is all that is required in federal court.  Precise contentions can be determined through discovery.