Recently wen i cleaned my Forge DV and stripped and regreased it i noticed a very small stepped ring at the base of the piston... im guessing that will make it leak? To test it in water for a leak i need to preasurise the side of the dv? and the small pipe on the top to the same level? My car sounds like an externaly gated rally car if i lift off from part throttle ... spring? faulty DV? needs shimming? bad map?