Mercury 2005 Mountaineer Owner's Manual page 276

Unleaded Gasoline engines
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.
FFV engine (if equipped)
Your FFV will operate well on ordinary "Regular" unleaded gasoline, but
only the highest quality fuel ethanol will provide the same level of
protection and performance. To identify if your vehicle is an FFV, check
your VIN or the label on the inside of your fuel filler door. When
checking the VIN, look for the engine type identifier (8th character). If
your vehicle is an FFV, then the character will be labeled as a "K."
If you operate your vehicle 50% or more of the time on ethanol, you
should follow a different maintenance schedule. See the Scheduled
Maintenance Guide for more information.
If you are experiencing a rough or rolling idle after start-up with the
outside temperature above 80° F (27° C), the idle should improve within
10 to 30 seconds. If the problems persist below this temperature, see
your dealer or a qualified service technician.
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:
• You may need to cycle the ignition from OFF to ON several times after
refueling, to allow the fuel system to pump the fuel from the tank to
the engine.
2005 Mountaineer (mnt)
Owners Guide (post-2002-fmt)
USA (fus)
Maintenance and Specifications
275