i knocked my cam interupt out of place installing the front cover the first time. it's not hard really, all i did was bump it
take the sensor out, get a mirror/flashlight and slowly rotate the motor until you can visually verify that it's still there. mine was there, but i bent the tabs and it got pushed back
check the harness wires where they run behind the waterpump pulley. it's also common for the pulley to chew through those wires if the harness is not routed correctly