cdvyas

Hello everyone, ever since I have had my 1MZ powered Avalon, I notice a buzzing noise from engine past 4k rpm and lasts all the way till the redline until it upshifts. The engine is very smooth and responsive but I wonder what that "zzzzz" noise is... other than that I don't even hear the engine that much. Is there anything like VVT kicking in like VTEC in rival brand past 4k, because it specifically comes past 4k rpm. Almost sounds like pinging but I put midgrade in and have tried premium and it still does that. Does anyone else have that sound past 4k?