Why does my Audi A4 make a rattling noise when I accelerate on the highway?

I've noticed that my A4 makes a rattling noise when I'm accelerating on the highway, but it seems to go away when I let off the gas. Any idea what could be causing this? Is it something I need to get checked out?

It sounds like you may have a loose heat shield. This can be caused by rust or weak clips. I recommend taking your car to a mechanic to have it inspected and repaired if necessary.

I had a similar problem with my A4 and it turned out to be a faulty exhaust valve. I would suggest having a mechanic check your exhaust system and do a compression test to diagnose the issue.

It could be a problem with your fuel injectors. You may want to clean them or have them replaced. If the problem persists, it's best to bring it to an Audi dealership for further diagnosis.