Can anybody recommend one? Specifically I need help with our Toyota Previa. The check engine light is on, and I have already replaced the EGR Valve, Vaccumm Modulator, O2 sensors and spark plugs. The throttle body was also cleaned out too. I took it to the dealer out in CA before I left for TX and they said it's the vaccumm switch. Anyways any recommendations will be greatly appreciated. Thanks.