All Saabs from the old ones to the new ones can run on all grades of fuel above 89 octane (Steve kindly brought this up as you will see later) because the systems are designed to adjust the ignition timing according to knock in the engine. When the sensor detects a knock the ignition timing is reduced in-order to eliminate the knock. Keep in mind that running higher octane fuel generally allows for better performance especially in any AERO Saab.
Thanks to Tim Waddingham for contributing to this FAQ!
I received a letter from SAAB stating that I should not use 85 octane fuel in my 9-5. If I did use 85 octane fuel - any engine damage would not be covered under the warranty. 85 octane fuel is sold as "Regular" in higher altitude areas like Denver. 87 octane is "Mid Grade" and "Premium" is only 91 octane. We can't purchase any higher octane from a regular gas station.
Thanks to Steve Karlovic for contributing to this FAQ!
I disagree with the statement that "All Saabs from the old ones to the new ones can run on all grades of fuel". My 9-3 Turbo requires 89 octane or better,as it says in the owners manual. On several occasions, I have tried to use lower grade gas, and each time it has led to hard starting and on occasion "check engine" light warnings. The dealer has confirmed that this is a common problem, and that the owners manual reads that way for a reason.
Thanks to Brian Darley for contributing to this FAQ!
Better performance from higher octane fuel includes better mileage for my 1999 9-3. The additional mpg is enough to make up for the extra cost per
gallon of Plus vs. Regular. Going to Supreme from Plus works out slightly more expensive in highway driving. So I find Plus is a good compromise.
Experiment on your Saab and see what works best for it.