A mate of mine is struggling trying to find whats causing a problem with his Seat Ibiza Cupra. The electronically controlled valve that operates the vacuum feed to the dump valve is opening the dump valve whilst its under acceleration. You can hear air gushing from the dump valve as the car hardly accelerates and then eventually it snaps shut and accelerate as it should. He has changed all the electronic valves and the only way I can get it to work properly is to disconnect the electronic valve and get it to run solely on the inlet pressure. Any ideas?