“Hubcap” (* out of four) was the film equivalent of a flat tire about a small-town sheriff (Holly A. Morris) in a mountain town who is investigating a supernatural serial killer but at the same time has to juggle her love life and various eccentrics (Adam Boyer, April Tweedy, and others) in her life. Jumbled and incoherent film can’t decide whether it wants to be a witless comedy or a ridiculous thriller and winds up stalling (and failing) at both. The kind of movie that cries out for the offbeat touch of the Coen Bros and is in serious need of a tuneup.