1987 944 engine cam noise

Hello,
I just bought a 1987 944. It runs great but there is a kncking noise coming from the top front of the cam cover. It sounds like a diesel at idle. When you rev it up it runs very smmoth. Oil pressure is great, power is great. Does anyone know what this could possibly be? your help would be greatly appreciated.

im not the best at these things, but im picturing it to sound like my old 88 accords "knicking" noises caused by valves in need of adjustment.

You may have a jammed lifter. When you rev it it builds up pressure and frees the lifter.

Also you may want to hook up a oil pressure guage if you havenet already. Because the guages in the car can be faulty.

Good luck