FORD 2010 Mustang v.1 - Manual (Page 287)

Note: Use of any fuel other than those recommended may cause
powertrain damage, a loss of vehicle performance, and repairs may not
be covered under warranty.
Octane recommendations
Your vehicle is designed to use
“Regular” unleaded gasoline with a
pump (R+M)/2 octane rating of 87.
In high altitude areas, we do not
recommend the use of any “Regular”
fuel with an octane rating below 87.
Do not be concerned if your engine sometimes knocks lightly. However, if
it knocks heavily under most driving conditions while you are using fuel
with the recommended octane rating, see your authorized dealer to
prevent any engine damage.
Octane recommendations (4.6L V8 engine)
Your vehicle will run normally on 87 octane regular fuel without
damaging the engine, but premium fuel with an octane rating of 91
(R+M)/2 or higher is recommended for best overall performance.
For Shelby GT500 octane requirements, see the Shelby GT500
Supplement.
Fuel quality
If you are experiencing starting, rough idle or hesitation driveability
problems, try a different brand of unleaded gasoline. If the problems
persist, see your authorized dealer.
Do not add aftermarket fuel additive products to your fuel tank. It
should not be necessary to add any aftermarket products to your fuel
tank if you continue to use high quality fuel of the recommended octane
rating. These products have not been approved for your engine and
could cause damage to the fuel system. Repairs to correct the effects of
using an aftermarket product in your fuel may not be covered by your
warranty.
Many of the world’s automakers approved the World-Wide Fuel Charter
that recommends gasoline specifications to provide improved
performance and emission control system protection for your vehicle.
Gasolines that meet the World-Wide Fuel Charter should be used when
available. Ask your fuel supplier about gasolines that meet the
World-Wide Fuel Charter.
87
(R+M)/2 METHOD
2010 05+ Mustang (197)
Owners Guide, 1st Printing
USA (fus)
Maintenance and Specifications
287