Hello all, new to the forum here. I have a 2006 mazda 3i with 78k miles. I have a question regarding a light grinding/ rattling sound I am hearing from my engine bay. It only occurs when the car is in gear and in motion. It occurs in every gear. When I lightly press the accelerator in any gear the noise occurs, as soon as I let off the accelerator it stops. It doesnt do it in park or neutral when revving the motor. I had a mechanic check the heat shields, all seemed ok. Also, The noise only occurs when the car is cold or cool, not when its hot. I was thinking of raising the front end of the car off the ground to where the wheels could freely spin. Then have someone lightly accelerate and try to pinpoint the noise myself. Would doing this be bad for the transmission? Oh and its not my motor mount because I just had that replaced by the dealer. Thanks for any replies.

 

on the passenger side of the car check the bearing in the middle of your cv shaft. its bolted to the engine. mine made the same sound and that was the problem

 

It could also be the vvt on the car. When you push the gas it is changing the timing for better performance. It won't do it when the car is not under a load because the computer tells it that it doesn't need to

 

Derek,

I am currently experiencing the same problem. Did you ever figure it out?

 

Under load vs not - the other thing that moves is the engine mount - or specifically something stuck in the engine mount (rock etc...). I think the #3 mount was recalled through the 2006 model year. It's the one on the top passenger side of the engine, see if it's leaking oil.