If the spark plugs on a Ford Ranger 3.0-liter engine malfunction, they will cause the mixture to be off at the very least, or they could cause excessive misfiring. The spark plug wires should be replaced at the recommendation of the manufacturer, usually every 30,000 miles. You can see if the insulation is bad by starting the truck, then misting the wires with a spray bottle of water. If you see one or more of the wires arc, replace the wires, no matter how "young" they are.
Instructions
- 1
Remove the plug wires from their box and lay them out on the front of the vehicle.
2Pull and twist the first wire closest to you off the spark plug. Follow the wire up to the distributor, and pull and twist it off the distributor cap.
3Match the wire with one of the new wires, choosing one of the same length. Press the wire firmly onto the distributor cap until you hear or feel it click into place.
4Route the wire to the spark plug, making sure you fit it back into any wire looms or brackets that the old wire came out of. Push the wire onto the spark plug. Again, you should hear or feel it snap into place. Repeat the process for all six plug wires and the coil wire.
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