Hi. I have a malfunctioning T4. Was running well then one day wouldnt start. Now it starts sporadically, idels fine, runs a bit rough. Then wont start. Sometimes smokey, then other times no smoke. Put "launch" on the ODBII & it spits out "sporadic fuel metering valve errors. Mechanic advised that car not worth putting new pump on.
Anyway, I noticed(front of motor between block & belt cover) the arm on the injector pump belt tensioner really jumping around a lot. Touched the arm lightly & the engine stopped straight away. Pulled the cover off & found the belt had 30-40% of the teeth missing & I was unable to spin the tensioner but able to spin the idler. The belt looks in extremely poor condition having only done around 60-80k km. I am wondering if the tensioner is seized & that is the clicking noise that I can hear & also a kind of light roaring noise when the motor is revved?
My main question is , can the belt cause the errors on the fuel metering solenoid? I would hate to go through the process of doing the belt to find that the pump is actually stuffed.

Thanks in advance.