Porsche Raspberry & CIS Warm Start Resolved
 

Do I need to be concerned?

I've been really shaking down the car recently after a top end rebuild. A noise started recently, like a high pitch continuous rattle, after start up. Tends to go away if I've been driving for a good while. Listen for the high pitch below. Sort of like a continuous high pitched raspberry (those with kids will appreciate). Seems to emanate above/around intake runner on cylinder #4.

Porsche Raspberry.

Any thoughts fellas?

Also, thanks to many, including Tony (Boy911sc), who have helped me chase a warm start problem for the past several months. I checked accumulator, then check valve at FP as well as the FD. Everything seemed ok. Finally got around to swapping out the injectors and VOILA! Warm start problem seems to finally have one away.

Thanks to all those that helped on that!
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I had a loose intake gasket make that sound. A leaking gasket can vibrate like a reed. Just my guess.

Get a hose, place one end in your ear and the other near the source to pin point it.

Good idea.