I am running very low on ideas of what the problem could be at this point, pretty much just crossing my fingers the car doesn't fall apart every time i get in for a drive i still get a strange high pitch whine at idle when the rpms are low enough but now i have a new noise my car is making and it is a painful sound i cant find the source of... The noise seems to be happening more frequently now across more rpms but it mainly happens when say im in 4th gear going 60km/hr and i step on the gas a little it makes a loud grinding/screeching noise for a second and then will trail off as i pick up more speed its throwing me in a loop because i cant recreate the sound when the vehicle is not under load and when i do a pull in 2nd gear going 40km/hr it still pulls hard and the noise seems to be less apparent as i am getting on the gas. Lately its getting very bad on the highway when im going higher speeds like ill be doing 120km/hr in like 6th or 5th gear and when i step on it a little to speed up or pass someone it makes the horrible grinding noise! its loud and I'm pretty sure it can be heard from outside the vehicle i feel like im kind of SOL at this point but if anyone has ideas please help. I have replaced the belt tensioner along with the serp belt already with no change.

 

Heat shield vibrating? Crawl under the car and manipulate parts of the exhaust, you'll prob find a loose piece.

 

This is what i was thinking originally a loose heat shield or just general resonance from the exhaust but the noise i am hearing changes drastically depending on speed and rpms I'm in its such an erratic noise when i hear it sometimes i mistake it for driving quickly by a car that is honking and i can not replicate the noise unless the vehicle is under load.

 

Please take no offense, but I think your being a little over dramatic regarding this "sound." From what I hear, it sounds like resonance from the exhaust. That, and/or a heat shield rattle/issue which these cars are known for. Naturally, the sound is going to be more pronounced, or louder, as the engine is under WOT. Is this exhaust OEM or aftermarket?

Nothing in that video leads me to believe that your car is going to "fall apart."

As Jsolo suggested, check your heat shields. I would also look for any signs of leaking exhaust gaskets or other issues with the exhaust piping. Unless the car is exhibiting driveability issues (like a vibration), I wouldn't worry.

 

No offense taken! If this is the case that would be the best scenario possible haha, The only reason im led to believe its not my exhaust is because i cant replicate it when not moving which i understand the exhaust would have a different resonance when under load but also i have another issue with noise where when im idling with most accessories off when the rpms drop low enough the car will start to emit a constant high pitch whine/buzz noise so i assumed that those two noises were somehow related. Either way through my troubleshooting i have found that the car has all original pulleys still and what i believe was an original serp belt this is on a 2010 with 140k so ive been replacing these piece by piece but still no change to any noise with new tensioner and new belt so far.

Also yes the exhaust is aftermarket its a custom built system copied from the Speed Culture Studios set up.