I bought a 1999 Boxster with 17,000 miles on it several years back. The engine sounded perfect until the first oil change. After that I started getting a tappet noise which DOVE ME CRAZY! The local Porsche dealer did the oil change. I brought it to another garage that specializes in Porsches and they ran lifter cleaner through it which did not help.
The problem was this: when the engine was cold it was quiet but after I drive it for a while I could hear tappet noise with the top up, or when I was at an idle with the top down. When I revved the car the noise would go away for a sho