I have been having starting problems, misfiring, and excessive NOX emissions. I replaced the fuel pump, worked good up till now. I was told to check the CMP and the crank shaft sensor. I can see the crankshaft sensor but dont have a clue where the CMP is This is a 2000 4.0 ranger 4X4 short bed. Some times it back fires out intake and some times the exhaust. Installed new heads water pump plugs n wire , coilpack less than 6000 miles ago. Failed the smog test twice with excessive NO emissions all the other ones were below normal. I am in Ca and dont know if my truck is CA or 49 state. The test station wants $200 just to tell me whats wrong. Any help here, and thanks
Ken