the truck was running fine and then one day it stalled like it ran out of gas. I popped the hood and there was a clicking noise, i tracked it down to a fuel pump relay, replaced it. The clicking stopped but it still stalls at idle , and smokes, and lightly drips water from exhaust pipe. the check engine light came on. Also the engine runs really rough at idle. Haven't driven it since. Does anyone know what this could be. Pleasse Help!