Running on empty when not on autopilot, the fourth film in the fast-car franchise sidelines its illegal street-racing base for an exhausted drug-running plot. The tragic death of somebody he loves brings Vin Diesel out of exile and back to LA, where he is forced to join up with his former enemy, FBI agent Paul Walker, if he is to nail the killer. Ignoring the prior two episodes, this weak sequel to the first film re-teams original stars Diesel, Walker, Michelle Rodriguez and Jordana Brewster in a barely credible story punctuated by scantily clad babes, macho posturing and extreme drag racing (emphasis on the drag). Even the initially intriguing chase scenes through the tunnels at the Mexican border become repetitive after a while. And a predictable romantic subplot involving Walker and Diesel's sister (Brewster) is resurrected, along with every hot rod movie cliché going, in director Justin Lin's tired turbo-drive through the action motions.