[V8] Excessive Oil and Emission Pressure

[ville.hiivola at suomi24.fi]

Hi, i have the same whine too from somewhere around the fuel tank. I 
don't think it's the pump, because it still sounds after you shut down 
the engine. When driving, it kind of changes pitch by throttle on slow 
speeds. On higher speeds its unnoticable. When engine is not running, 
the sound comes in periods of 5 seconds or so and if i open the gas cap 
it stops. A guy on another forum said it might be the gas cap not 
releasing the pressure properly, im not sure if that could be the case 
here since i dont know how to test the cap.