I have hooked up a oil pressure hook up to a 5th gen and I am getting 1 kgf/cm2 at idle and 4kgf/cm2 at 3k. This meets spec however I notice a whenever it reach to 6kgf/cm2 (at around 4k rpm) the pressure will drop about 1kgf/cm2 then it will continue to go back up. This happen on the consistance at low and high temperature and at all gear. Is there a release value that keep on the car under 6kgf/cm2 or did I do something wrong?