I just started to notice a loud "howl" noise at 6500RPMs. It's not there at any other RPM and sounds like it's an intake noise not exhaust. The doughnuts were replace 2k miles ago with copper and when I have it on a stand it doesn't seem to make the noise. The sled runs fine and doesn't skip or bog at 6500 just the loud howl that goes away once the rpms drop or increase. I checked the airbox and it seems fine. No codes either, and as mentioned it seems to be coming from the intake side of the engine.
thank you for any information or thoughts.
thank you for any information or thoughts.
