FORD 2003 Mustang v.1 - Manual (Page 218)

Fuel quality
If you are experiencing starting, rough idle or
hesitation driveability problems during a cold start,
try a different brand of “Regular” unleaded gasoline.
“Premium” unleaded gasoline is not recommended
(particularly in the United States) because it may
cause these problems to become more pronounced.
If the problems persist, see your dealer or a qualified
service technician.
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.
Aftermarket products 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 issued 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. In
Canada, look for fuels that display the Auto
Makers’ Choice
௢ logo.
Cleaner air
Ford endorses the use of reformulated
“cleaner-burning” gasolines to improve air quality.
Running out of fuel
Avoid running out of fuel because this situation may
have an adverse affect on powertrain components.
If you have run out of fuel:
Maintenance and Specifications
218