Hi guys, i have 2000 SC300 with 112,000 Mile on it. i drive her mainly on cruise control for going to work and come back home. recently i noticed a rhythmic reeving noise coming from the engine. it happens while i am driving on a constant speed around 2000 to 2300 rpm or 58 to 63 MPH. the rhythmic noise is at most around 2100rpm using the cruise control. if i park the car and place it neutral and rev around that same rpm then i dont hear it but i only herar this noise when i am driving. i do have a engine trouble code but it was determine to be a EVAP system and recommend charcoal canister replacement with vacuum switch valve. is this related issue?

 

it maybe something simple as a v belt.

 

Is it only at that rev range or only at that speed? Have you tried dropping it out of overdrive to change the RPMs at the affected speed and see if the sound goes away?