Mark, Intermittent fault. Resistance check of the solenoid was good. Cant find any test data for solenoid or make any sense of how it works (Doesn't seem to be a straight forward open/closed solenoid valve) Vac pipes atc all good, Boost diaphragm OK. Would love to test and confirm valve but cant see that its possible at the moment. Seems like the valve is my best option. Always willing to learn, any other ideas or info to help me confirm would be great.

Steve.