The owners manual shows ( Motorcraft BXT - 65 - 650 ) That is Fords " top of the line "
battery for your vehicle
* that's BCI group size 65 , 650 cold cranking amps
You don't say which model year of Mercury Mountaineer but they have all used the ( BCI group size 65 battery ) such as the Motorcraft BXT-65-650
sometimes it is due to a weak battery.
# 24 is a 15 amp fuse for the cigarette lighter , OBD II , in the passenger compartment fuse panel of a 2004 Mercury Mountaineer
( # 24 ) is a blue color 15 amp fuse for the cigarette lighter and OBD II in a 2003 Mercury Mountaineer ( under the instrument panel )
Did you check the -- sending unit !!
you have 4 o2 sensors on the 2002 mountaineer. if you get under the car and look at the exhaust pipe where it goes up either side of the engine you will see it bolted into the exhaust, it has wires coming from it. they are the front 2, the rear 2 are about 2 feet farther to the rear (easier to see)
Get the alternator checked before your battery goes dead.
Mine did that and went away when I serviced the Transmission
Search: Double-Diode Isolation
5 quarts ( 4.7 liters ) with engine oil filter change
you will need a quick release tool it runs 5 dollars from any parts store it goes into the line and then pull the line out not easy it will take time with this car be patient and all will work out
my alarm goes off at random times. i had the alarm module changed for $700 and it still goes off. come home from work at 4 and it goes off at 10. before the alarm module was changed it went off at 12, 2 and 4 in the morning.