[jorian]

Premature valve-guide wear occurs because in the 3.2 cars, Porsche tightened the tolerances in the guide which can lead to an oil-starvation problem. This is more prevalent in southern cars exposed to higher average temperatures. A PPI will not always diagnose this issue. Run the car up to redline in 3rd or 4th gear and suddenly lift off, you'll get the highest possible vacuum sitation and maybe see a puff of smoke from the exhaust pipes of cars with worn valve guides. - Excellence