What movie am I thinking of?

I'm trying to remember what the name of this one particular movie was. it starts and mostly takes place at a diner. this guy comes in, talks to the woman. he has a stab wound or gunshot wound i cant remember. later it turns out hes a schizo, killed in the bathroom by electricity. theres these three surfer dudes who are trying to find him, they want this disk or something. when the schizo guy is taken to a doctor, the doctor is killed. it ends with a scene at a gas station, the surfer dudes kill the guy working there with a kinfe, and i think gets shot. it ends with gas going everywhere and lighting on fire.