There are ( 6 spark plugs ) on the Ford 4.0 liter V6 engine
On a Ford Excursion ( if it has a gasoline engine ) ( the 5.4 liter V8 engine has 8 spark plugs ) ( the 6.8 liter V10 engine has 10 spark plugs )
You need to remove the valve cover ((V8) motor) and remove the spark plug coils, then you can change the plugs.
If you have the original Ford plugs, you only need to replace them every 100,000 miles.
There are ( 6 spark plugs ) for the 3.8 liter V6 engine in a 2000 Ford Mustang
On a 1998 Ford Expedition : There are ( 8 spark plugs ) for the 4.6 and 5.4 liter V8 engines
( 6 spark plugs ) for your 4.0 liter SOHC , V6 engine
i believe a 5/8 deep well socket is the one.
That would depend on which engine you have in your 2003 Ford Excursion : The 7.3 liter diesel engine doesn't use any spark plugs The 5.4 liter V8 engine has ( 8 spark plugs ) The 6.8 liter V10 engine has ( 10 spark plugs )
to change the spark plugs first take off the plastic cover on top of the motor, the spark plugs are on the center of motor you see two coils on top of the two center spark plugs and two spark plugs wires going to the out side spark plugs you pull the wires off and you need a long socket wrench or a spark plug socket with extension bar to take it off, also you need to pull the coils to replace the center spark plugs they are under the coils. NOTE. this is for a four cylinder engine. excuse my English B. Cerda.
to change the spark plugs first take off the plastic cover on top of the motor, the spark plugs are on the center of motor you see two coils on top of the two center spark plugs and two spark plugs wires going to the out side spark plugs you pull the wires off and you need a long socket wrench or a spark plug socket with extension bar to take it off, also you need to pull the coils to replace the center spark plugs they are under the coils. NOTE. this is for a four cylinder engine. excuse my English B. Cerda.
you probably need new coil packs.