Check the plugs for deposits and wear. If they are not going to be replaced, clean the plugs thoroughly. Remember that any kind of deposit will decrease the efficiency of the plug. Plugs can be cleaned on a spark plug cleaning machine, which can sometimes be found in service stations, or you can do an acceptable job of cleaning with a stiff brush. If the plugs are cleaned, the electrodes must be filed flat. Use an ignition points file, not an emery board or the like, which will leave deposits. The electrodes must be filed perfectly flat with sharp edges; rounded edges reduce the spark plug voltage by as much as 50%.
Check spark plug gap before installation. The ground electrode (the L-shaped one connected to the body of the plug) must be parallel to the center electrode and the specified size wire gauge (please refer to the Tune-Up Specifications chart for details) must pass between the electrodes with a slight drag.
Always check the gap on new plugs as they are not always set correctly at the factory. Do not use a flat feeler gauge when measuring the gap on a used plug, because the reading may be inaccurate. A round-wire type gapping tool is the best way to check the gap. The correct gauge should pass through the electrode gap with a slight drag. If you're in doubt, try one size smaller and one larger. The smaller gauge should go through easily, while the larger one shouldn't go through at all. Wire gapping tools usually have a bending tool attached. Use that to adjust the side electrode until the proper distance is obtained. Absolutely never attempt to bend the center electrode. Also, be careful not to bend the side electrode too far or too often as it may weaken and break off within the engine, requiring removal of the cylinder head to retrieve it.
Removal & Installation
A set of spark plugs usually requires replacement after about 30,000 miles (48,000 km) on Flexible Fuel Vehicles (FFV) and about 100,000 miles (160,000 Km) on all gasoline engine models, depending on your style of driving. In normal operation plug gap increases about 0.001 in. (0.025mm) for every 2500 miles (4000 km). As the gap increases, the plug's voltage requirement also increases. It requires a greater voltage to jump the wider gap and about two to three times as much voltage to fire the plug at high speeds than at idle. The improved air/fuel ratio control of modern fuel injection combined with the higher voltage output of modern ignition systems will often allow an engine to run significantly longer on a set of standard spark plugs, but keep in mind that efficiency will drop as the gap widens (along with fuel economy and power).
When you're removing spark plugs, work on one at a time. Don't start by removing the plug wires all at once, because, unless you number them, they may become mixed up. Take a minute before you begin and number the wires with tape.3.0L (VIN S) Engine
- Before servicing the vehicle, refer to the Precautions section.
- Remove the upper intake manifold.
Disconnect the electrical connectors from the ignition coils.
NOTEWhen removing the ignition coils, a slight twisting motion will break the seal and ease removal.
Remove the bolts and the ignition coils.
CAUTIONOnly use hand tools when removing or installing the spark plugs, or damage can occur to the cylinder head or spark plug.
NOTEUse compressed air to remove any debris from the spark plug well before removing the spark plugs.
- Remove the LH and RH spark plugs.
To install, reverse the removal procedure. Tighten the spark plugs to 11 ft. lbs. (15 Nm).
NOTEApply a light film of Silicone Brake Caliper Grease and Dielectric compound D7AZ-19A331-A or equivalent meeting Ford specifications ESE-M1C171-A to the inside of the coil boots before installation.
On 3.0L OHV engines, if a spark plug is removed for inspection, it must be reinstalled in the same cylinder. Cylinders 1, 2 and 3 have a PG suffix and cylinders 4, 5 and 6 have a P suffix. If a spark plug has to be replaced, use only plugs with the service part number suffix letter PP as shown on the engine decal.
- Disconnect the negative battery cable, and if the vehicle has been run recently, allow the engine to thoroughly cool.
- Remove the right hand side of the cowl vent screen and the right hand cowl top extension.
- Unplug the engine control sensor wiring from the ignition coil, then unfasten the four ignition coil hold-down screws and remove the coil so that access to the spark plugs located at cylinder 1, 2 and 3 is possible.
- Unplug the electrical connection from the Intake Manifold Runner Control (IMRC) actuator, unfasten the actuator retaining screws and lay the actuator to one side so that access to the sparks plugs at cylinders 4, 5 and 6 is possible.
- Carefully twist the spark plug wire boot to loosen it, then pull upward and remove the boot from the plug. Be sure to pull on the boot and not on the wire, otherwise the connector located inside the boot may become separated.
Loosen the spark plugs
turn , then using compressed air, blow any water or debris from the spark plug well to assure that no harmful contaminants are allowed to enter the combustion chamber when the spark plug is removed. If compressed air is not available, use a rag or a brush to clean the area.
NOTERemove the spark plugs when the engine is cold, if possible, to prevent damage to the threads. If removal of the plugs is difficult, apply a few drops of penetrating oil or silicone spray to the area around the base of the plug, and allow it a few minutes to work.
Using a spark plug socket that is equipped with a rubber insert to properly hold the plug, turn the spark plug counterclockwise to loosen and remove the spark plug from the bore.
WARNINGBe sure not to use a flexible extension on the socket. Use of a flexible extension may allow a shear force to be applied to the plug. A shear force could break the plug off in the cylinder head, leading to costly and frustrating repairs.
- Inspect the spark plug boot for tears or damage. If a damaged boot is found, the spark plug wire must be replaced.
- Using a wire feeler gauge, check and adjust the spark plug gap. When using a gauge, the proper size should pass between the electrodes with a slight drag. The next larger size should not be able to pass while the next smaller size should pass freely.
Carefully thread the plug into the bore by hand. If resistance is felt before the plug is almost completely threaded, back the plug out and begin threading again. In small, hard to reach areas, an old spark plug wire and boot could be used as a threading tool. The boot will hold the plug while you twist the end of the wire and the wire is supple enough to twist before it would allow the plug to crossthread.
WARNINGDo not use the spark plug socket to thread the plugs. Always carefully thread the plug by hand or using an old plug wire to prevent the possibility of crossthreading and damaging the cylinder head bore.
- Carefully tighten the spark plug to 80-177 inch lbs. (9-20 Nm).
- Apply a small amount of silicone dielectric compound to the end of the spark plug lead or inside the spark plug boot to prevent sticking, then install the boot to the spark plug and push until it clicks into place. The click may be felt or heard, then gently pull back on the boot to assure proper contact.
- Place the IMRC actuator into position and install its retaining screws, then attach the electrical connection to the actuator.
- Place the ignition coil in position and install its retaining screws, then attach the engine control sensor wiring to the ignition coil.
- Install the right hand cowl top extension and the cowl vent screen.
- Connect the negative battery cable.