Usage of Premium/Regular Fuel
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The SVX and Legacy turbocharged vehicles require the vise of unleaded premium fuel with a rating of 91 AKI (Anti-Knock-Index) or higher.
Unleaded regular fuel with a rating of at least 87 AKI may be used temporarily when premium fuel is not available. However, when a regular fuel is used, the ECU will learn to run on regular fuel even when a small amount is used. This may cause engine knocking, poor driveability and poor fuel economy compared with premium fuel.
Even after refilling the vehicle with premium fuel, the ECU may NOT relearn quickly on how to run on premium fuel. This process will depend on the driving pattern of the user and the length of time the vehicle is driven. The best way to ensure the ECU will fully learn to run on premium fuel is to clear the memory using the Select Monitor. This will set the ECU back to the beginning of the learning mode.
NOTE: DISCONNECTING THE BATTERY OR THE ECU MAY NOT CLEAR THE LEARNING MEMORY COMPLETELY.
If you have a vehicle with a driveability complaint make sure you confirm with the owner the type of fuel that is in the tank before you attempt any repairs.