my mates 2wd cossie has just started to lose oil pressure on tickover its down to about 30 psi but when he gives it some it down to 20 this is at tickover but as soon as you drive it its about 55 all the time even after giving it some any ideas the engine had a freshen up about 4000 miles ago new rings and shells do you think pump is on its way out its a grahame goode uprated item if that helps also only 4000 miles ago. recent oil change no bits of metal inside any help cheers