What recourse do I have if they can't fix this issue?

My Honda 2016 HRV makes a weird kind of a rattling sound when accelerating at about 30 Mph. It is new and under warranty. They said they don't know the cause and unless a service bulletin comes out there's nothing they can do. What can I do here?

What's causing the noise is the CHEAP GAS you have in the car. Buy from a different place and put super unleaded in it and see if it doesn't go away. This sound is known as "labor knocking".

If it can't be repaired avail yourself of your states lemon law. Look the law up for you state to understand what you must do and the specifics of the law. BTW, it is NOT the gas you are using as your Honda is designed to run on Regular and if it is labor knocking then this is caused by the ECU not the gasoline you are using.

First, demand that they call Honda tech support. If that doesn't work, call Honda customer service and tell them the dealer can't fix the problem and you'd like them to open a case file. Then the regional service manager gets involved