I have an 86 mazda rx-7 N'A and at around 3000 RPM's i hear this soft whistle coming from the engine...when i hit the clutch to shif to the next geat it will go away and then when 3000 rpm's comes again i hear it...is this a sign that my engine is going out or that maybe i need to check my air intake system? Please help

 

@ just 3000rpm or 3K and higher?

 

it might be a muffler too

 

It may be your waterpump as well. Mine is kind of dying and it whirrs when i rev. Is your pump still good?