" regular " unleaded - 87 octane
They run fine on 87 Regular Unleaded
As much as the gas tank will hold... ---------------------------------------------------------------------------------------------- On a 1997 Mercury Grand Marquis , the gas tank capacity is ( 20.0 U.S. gallons )
According to the 2000 Mercury Grand Marquis Owner Guide : ( The gas tank capacity is 19.0 U.S. gallons )
For a 2005 Mercury Grand Marquis : " regular " unleaded , 87 octane According to the Owner Guide
18 MPG.
on top of gas pedal
Regular Unleaded.
According to the 2004 Mercury Grand Marquis Owner Guide : ( 19.0 US. gallons )
According to the 1997 Mercury Grand Marquis Owner Guide : ( 20.0 U.S. gallons )
The ( 2007 ) Mercury Grand Marquis has a ( 19 U.S. gallon tank )
approx 20 us gallons
According to my Chilton's Auto Repair manual : A ( 1987 ) Mercury Grand Marquis has a ( 20 U.S. gallon gas tank )