Octane vs mileage

My 2006 Lexus ES330 book says I can use High test mid grade or low grade gas. Does the high test give me better mileage?

If it does is the increased mileage enough to offsett the cost diference.

Jack Machun

San Rafael CA

Only you can tell with your driving and car. It is not likely to totally offset the cost difference, but it may. Consider that even if it does not fully offset the cost, you will likely be getting better performance with the higher octane.

Try it and see for yourself.

Try a tank or two of each and let us know how it works for you.

All we can say from here is that you will have to be your own expert.

Can you be more precise on exactly what the manual says? Does it say that 91 is recommended but it can run on lower octanes without damage? If so, that means the timing will be retarded with lower octanes, which should mean some reduction in mileage, though it’s hard to say how much. Measuring a few tanks of each is probably the best way to figure this out.

I’ve been using regular in my ES 300 for a number of years, I noticed no difference in mileage.