Hi, I have a Corolla S 2001 with 113k right now.
I've had it since it was 97k. Everything has been perfect with the car (I know the original owner and know how the car has been taken care of) as you can expect with a Corolla.
At around 107k I started hearing a noise (like a vibration that made a plastic bang against another) when I downshifted, it only lasted for a couple of seconds when the car was at around 2200 rpm.
I took the car to a place this friend recomended me (Toscalito, in Terra Linda) to see if they would tell me what the noise was and they found a couple of things (as they usually do ) and recommended rotors changed (they were warped) enginge clean, and they found out that the Engine mounts were loose and that could lead up to the vibration.
Stupidly, I decided that I wanted to get the engine mounts replaced (400 bucks T_T, let's get over that, i don't even want to remember it).
I did, and that's when my "problems" started.
The car runs perfectly, but the noise has increased, a lot, at least a lot for me.
If I throttle the car while parked, I hear the engine humming, as it normally would on higher RPM but this time, at a lower. I'd say that noise scale has been changed and it starts 25% before than before.
(when I can I'll upload a video to try and illustrate the issue)
I complained to Toscalito, they rechecked the mounts and claim that they are fine, and that the reason why i feel this is because now the mounts are not loose anymore and therefore the vibration that the engine was making, now it's being transmitted directly to the car.
Also, as you can imagine, the vibrations can also be felt in the front of the car where my headlight will "bump" with the fender resulting in a really annoying vibration noise.
I can definitely feel the difference in idle and also on the highway. When I'm doing 80mph the revs are around 2800 and it sounds like if they were on 3500 or something like that.
I'm a freak of nature when it comes to sound and driving like this drives me crazy to the point I don't enjoy it anymore and to me that's sad
I don't think brakes/tires matter but front/rear brakes are brand new and so are the tires(less than 2k)
I also changed the sparkplugs 1k ago. Nothing changed.
My mpgs vary between 33/35 depending on the usage (which is anyway mostly highway)
Any help on what the causes could be and what I could do to fix this would be greatly appreciated.