You know how over time arround old soldier you get that brown de-electite crap on it that fucks up connestions (like on most stock bose head units) get this stuff from Radio Shack its electrical cleaner I used it on my coil packs and I'm going to clean my injector connectors with it. Makes a big diffrence in my opion. It too also helps prevent corrosion. (Flame suit on for those that wish to argue and I know someone will)