Dear Doctor: I’m looking for the definitive answer on whether it is truly mandated that premium gas be used in the Nissan Murano as suggested by the manufacturer. I’ve been told that it is not a problem to burn regular gas. There is obviously a reason why the manufacturer is recommending premium gas. It has always been my contention that various sensors in the vehicle are set to monitor the consumption of a specific octane and that you could disrupt the sensor’s function by burning the wrong gas. Can you hurt the engine by extensive use of lesser octane over a several year period? Mark
Dear Mark: The engine in your Nissan is a high performance V-6. The engine is high tech with high compression and variable valve timing with 24 valves. The fuel delivery is also precise. The lower octane gasoline burns off at lower heat than the high octane. They both have cleaning additives. The use of regular octane gasoline will limit the power under hard and full acceleration. It will not cause hesitation, but it will cause additional carbon buildup in the combustion chambers. The 20-cent a gallon difference only equals a few cups of coffee a week. I personally would not make it a habit to fill the tank with regular unleaded gasoline. The gas mileage will also be lower with the use of regular unleaded. When it comes to gasoline put in what the manufacturer recommends. Also, the use of full-synthetic oil can increase gas mileage up to 1-mpg, which helps make up the added cost of the premium fuel.