Hey guys please help me!!!!

My car is making a similar sound to some others I’ve seen online, but mine almost sounds like a ratchet. My car is very low on BC Racing coilovers, and I can only hear the sound at low speed, only when taking off. It happens consistently at around 1500–2000 RPM, then goes away after that or if I let off the gas. Even if I just rev it in park, neutral, or at idle, I hear nothing. If there’s not too much external noise, I can hear it clearly from inside if i have my windows down, but it’s even more noticeable from outside the car. I believe the sound is coming from underneath, because when I’m driving slow through a parking lot I hear it echoing off the ground and surrounding walls. A mechanic quickly checked under the car with a stethoscope and around the engine, but I feel like he’s wrong — he didn’t take much time because he was busy. He told me to replace three engine mounts (front, rear, passenger front) and the lower transmission mount, but I’m not confident in that answer. He didn’t test drive it or thoroughly check things, and I really don’t want to start replacing parts without knowing for sure. Has anyone dealt with something like this? I’d really appreciate any help figuring this out.

 

check the heat shields on the engine catalysts, sometimes they rust and vibrate at lower RPM's causing a sound similar that. Cheap fix is to put a clamp around it and tighten it down:
https://www.mdxers.org/threads/heat-...-repair.47437/