[offtopic]Yes there are issues with the car. I just recently took over maintaining/using it from a family member since they can't drive much anymore. They had it for about 5 years and did NO maintenance (not even fluid or oil changes). It ran worse than now. Too many repairs needed to list. Considering the shape and miles of the car.. 23mpg isn't bad at all lol. [/offtopic]
Quote:
Originally Posted by F8L
You may want to have your car diagnosed. There is no way you should get 10mpg better fuel economy between 87 octane and 91+ unless there is a problem with the car. Higher octane contains less energy due to reduced burning efficiency. You may have a problem with a knock sensor which causes a reduction in ignition timing and therefore efficiency. In very high mileage "engines, the build up of carbon deposits on the pistons can cause similar issued by raising compression ratio or creating hot spots.
No matter what the cause, there is no way that you would observe such a difference in mpg in a properly running vehicle (designed for 87 octane) by the simple addition of higher octane fuel. This has been tested quite thoroughly.
|