Hey people hows it going? Alright im back again to ask yet another question. This one isnt about anything thats broken surprisingly but just a noise that i hear. Ok so let me explain: if my cars in park and i rev the engine it makes a weird noise. It sounds as if the engine is like fighting back almost and it comes from right under the bottom of the bulkhead and under the floorpan But if the car is in neutral and rolling and i rev it the same way to the same amount it doesnt make the same noise. And if its in drive and i romp on the gas and the revs go to 4500-5000 it doesnt make the noise either. I have no idea what it is and im not too worries about it but im just curious on what it is. At first i thought the cat but if it was itd make the noise all the time right? Im thinking it might be something like the engine when the rev likiter kicks on or the transmission fighting back because its not moving? I have no clue does anyone else have any idea?

 

theres really not much to say to this...but yet a whole bunch that could be said....and with that being said a few guesses could be maybe a loose heat shield, a motor mount or flywheel. trany shouldn't be affected till its in gear, a cat wont make any noise like that. my main vote is a motor mount tho. have someone look at your engine while you rev it and see how much your engine moves when you are revving it up.

 

This might be obvious... Or the answer to your question...
In park our cars have a lower rev limiter right around 3500-4k rpm. It cuts the fuel out if you hit it, and sounds like a waah or waah waah waah sound if you keep the throttle on. Is this what your hearing?