I have a 2015 lexus es3350, when i go over bumpsor cracks on the road i hear rattle as if something metal is moving or hitting something. I changed my sway bar links ( it was making the sound before changing as well) and i checked my sway bar bushing and the sway seems to be tight. the sound mostly comes from the middle to passenger side front (I even tore the centre console area to see if something is loose AND changed my sunroof rubber seal because i thought it would be the sunroof rattle). the sound does not come if i hit pot holes that are sunken in the road if you understand what i mean; but rather its on cracks and bumps on the road. I am super annoyed and cant seem to find the solution. I even checked the heat shield and checked the exhaust as well.

 

That metal noise could be a heat shield. There is one to cover the exhaust manifold at the front of the car by the radiator, and a few to cover the exhaust pipes all the way back to the end bumper.

When the car is cool. Get underneath and gently bang on the exhaust pipe to see if you can duplicate the sound. Also, gently bounce on the bumpers at each end and again see if you can duplicate the sound.

I replied to your other post about my rear heat shields dangling and banging around.

 

Yes I believe you posted the video. I tried that and it was tight. I will try your new recommendation...hopefully it is that. Thank you!

 

I checked the shield by the rad as you suggested and it is solid tight

 

Check the catalytic converter.

 

Try going over bumps with your sunroof open. I found that was happening to mine but I couldn’t figure out where the sound was coming from. Finally narrowed the sound down to the sunroof wind deflector. You know that little piece that is spring loaded that pops up when you open your sunroof? That one. Let me know if that sound stops when you hit bumps or turns when you have it open.

 

Think I found it, and it's finally fixed for me...
Now comes the questions tho...

Weird knocking sound - ClubLexus - Lexus Forum Discussion

 

I had the same issue and also changed my sway bar links because I was certain that's where the noise was coming from and owned other cars where that occurred and it fixed it. I thought it was weird to have a suspension problem on a relatively new car, but I went ahead and did them. It didn't fix the knocking.

Turns out it was the sunroof, something like a cable that became detached. Common problem with the ES, fortunately the dealership covered the repair. Never dreamed the noise was that, I was certain it was coming underneath the car and was suspension related.