aah. now i know what you mean. i know it by diffirent name, but now i remember that i have heard that phase sensor too. well, you live and learn.

i doubt that its that, but its surtainly worth of checking.

first check the sensor itself that it isnt damaged at any way, then clean it, if dirdy.
clearance of phase sensor to cam, is 0.2-0.3mm.
resistanse between 23 pin and 5 on ECU multiplug is 700Ohms to 1.2kOhms. if that is not correct, you need to check wiring of phase sensor to ecu.