( 1 ) PCV valve for your 5.0 liter / 302 cubic inch V8
The Owner Guide shows Motorcraft EV-152 and fordparts.com shows Motorcraft
EV-152-D as the part numbers
The check " gage " light on in your 1997 Mercury Mountaineer indicates that either your engine oil pressure is LOW , your engine temperature is HIGH or your gas tank is AT OR NEAR EMPTY .
According to the 1997 Mercury Mountaineer owners manual : Your 4R70W automatic transmission capacity is ( 13.9 quarts ) * that of couse would be for the transmission , torque converter , lines , transmission cooler , etcetera *
12 city / 17 highway ( according to fuel economy . gov )
( 2 ) There is a fuse panel in the end of the dash on the drivers side ( the plastic fuse panel cover is visible with the drivers door open ) and the Power Distribution Box in the engine compartment on the 1997 to 2001 Mercury Mountaineer
the four door speakers are 6x8 and the sob if you have one is 8"
There are two head gaskets in the V 8 1999 mercury mountaineer
According to the 2004 Mercury Mountaineer Owner Guide : ( 22.5 U.S. gallons )
There are a total of ( 4 oxygen sensors ) according to the engine wiring schematic for the 1997 Mercury Mountaineer in my Haynes repair manual ( 2 oxygen sensors are " upstream " sensors used by the PCM to adjust the air / fuel ratio of the engine ) ( 2 oxygen sensors are " downstream " sensors / catalyst monitors )
Two.
According to the 2007 Mercury Mountaineer Owner Guide : ( there are 5 lug nuts per wheel )
22.5 gallons
4