Hi... does any one know or has heard about a fault that requires the fuel evaporation valve replacing? I have a slight popping noise when my car is idling, I thought it maybe due to the cat breaking down, but am unsure. also when I asked vauxhall about the evaporation valve they said theres never been a case where someone has ordered the part (p/no 9157542), if any one can shead some light on the subject or advise me how exactly the valve works it would be great, I also found there was no 12v supply to the valve. unfortunatly I have no wirering diagram so I cheers.. cant see where the supply comes from look forward to your thought chaps.