Ford equipped the 1999 Expedition XLT and the Eddie Bauer Edition with the 240-horsepower, 4.6-liter V-8 engine as standard equipment. The 260-horsepower 5.4-liter V-8 engine was an option available for an additional $665. Though gap and torque specifications are the same, the spark plugs required for each are different.
The 4.6-liter engine uses different spark plugs for the left bank and right bank of the engine -- AWSF32P and AWSF32PG, respectively. If you reinstall the old plugs, make sure you reinstall each plug into the same cylinder from which it was removed. Replace plugs on either side with the base part number suffix "PP" -- AWSF32PP -- as shown on the engine decal. Gap the plugs to 0.052 to 0.056 inch and tighten them to 15 foot-pounds. When installing the spark plug wires, use Silicone Brake Caliper Grease and Dielectric Compound D7AZ-19A331-A or equivalent meeting Ford specification ESE-M1C171-A on the inside of the spark plug wire boots.
The 5.4-liter engine with two valves per cylinder or four valves per cylinder are different only in the spark plugs used. The two-valve 5.4-liter engine uses AWSF22E plugs and the four-valve engine uses AWSF32P plugs. When you install the plugs, set the gap to 0.052 to 0.056 inch and tighten them to 15 foot-pounds. When installing the ignition coil boots, use Silicone Brake Caliper Grease and Dielectric Compound D7AZ-19A331-A or equivalent meeting Ford specification ESE-M1C171-A on the inside of the boots. Tighten the ignition coil bolts to 9 foot-pounds.
