OC:

Consider installing a WUR bypass line equipped with a needle valve, so that you are able to set the control pressure manually.

Cold control pressure should be under 20 psi., rising to ~ 50 psi. when warm. By setting the CCP manually it will be possible to isolate the WUR from the fuel distributor (FD), and perhaps determine if there is a fault in the FD as well as the apparent fault in the WUR.