2003 Volkswagen GTI Oil light and noise.

Hey guys. Several months ago. The timing belt broke. Valve repairs, new gaskets, new belts, all new coil packs. Some other things were damaged due to miles and plastic parts breaking. Almost all were replaced. But first the oil light issue. It never did this before the breakdown, but now I drive, no problems for about 20 minutes and the oil light will flash and as I slow down, the rpms reach 2000 and it makes a chattering noise. Last I checked oil pressure was within specs according to alldata. Im a kia service tech by the way. I can feel more of the noise on top of the valve cover close to the pipe that connects to the last broken piece I havent replaced yet. The car can be started and ran for hrs and the light and noise will not happen at idle. But get in and drive. 15 to 20 minutes later, light and noise hapoens. The pipe I need to know what it is called so I can replace it. At one end it connects to the air inlet pipe before the turbo but after the maf. A diverter valve I think. Ok, it leaves there and also connect to the valve cover, then goes down and to the left and connects to some sort of t block under the intake manifold. Lol. Any idea what I'm tryin to describe to ya. Vwpartsoem website has lots of diagrams that have proved useful, but not for this particular part. Thanks for ur time.