since i've installed a new violet BVSV, i now hear a whistle sound between 2,000 ~ 2,000 rpm in any gear. i cannot hear the whistle when the truck is stationary and reving to that rpm. i can control the pitch of the whistle using the gas pedal. when driving, once i step on the clutch, the whistle disappears. i took my truck to a shop yesterday and lifted it while the rear wheels were free. i took 2nd gear up to the rpm and no whistle. the whistle also comes with some slight chugging similar to a vacuum leak. any ideas to this madness? i've checked for leaks around the intake and carb. no issues found.