I am looking to buy a 2006 Acura TL which recommends using 91 octane fuel. Can I run the vehicle on 89 or 87 octane ? I know there will be a lose of performance, but will there be any harm to my engine ?
Most modern vehicles that require premium fuel can run fine on regular gas. However, you will see reduced performance and reduced fuel economy as a result. Reducing the fuel economy by using a lower octane gas may negate the cost savings.
Another reason to use premium in a vehicle designed for it is warranty service. If you bring your vehicle in for service because of some sort of mechanical problem, and the technician discovers that you are not using premium when it is called for (they can test for this), you could have your warranty coverage denied.
For best results, always use the grade of fuel recommended as it is written in either your owner's manual or on the inside of your gas cap door.