hi am suspect that my cam has had it as over the weekend the lifter on no 1 cylinder starts to tap realy load when u give it some large and take it above 4500rpm then takes about a 1min to quite back down i have changed that lifter as i thought it might be a faulty one but it just started doing it again i was going to change the cam the weekend but had so much to do on the car dident get around to it and the new cam i have got is suposed to make the car laggey. has any one got any ideas to what it might be causeing the lifter to tap and then go quite ?has anyone else had this problem?