Hey everyone. new to the forum. Purchased a new 2018 Elantra Value back in February. Went to dealer's service a few days ago for a few reasons; one being a barely audible noise that I hear when accelerating usually around 3rd gear topping just over 2000 rpms. Very hard to hear but definitely there. I read some older threads but thought I'd open it up again. Dealer said that that they did hear it and replaced the knock sensor and didn't hear noise after. Well, the noise is still there and my paperwork doesn't show the part replacement and interestingly says couldn't duplicate noise. Why I didn't question this at the time is another story; I had other battles to fight with them. I have another appointment in a few days and this will obviously be brought up again. So, any advice on this? I don't think I should have to just live with this noise.