The F-150 had a somewhat humble beginning in 1975 as the bridge model between the light-duty F-100 and heavy duty F-250. In its first year on the market, the F-150 was a smash hit, as it accounted for over one-third of all F-Series sales, and it later became the best-selling vehicle in America. The 1999 Ford F-150 had an optional 4.6-liter V-8 engine that produced 220 horsepower.
The 1999 Ford F-150 with the 4.6-liter V-8 engine requires Motorcraft spark plugs No. AWSF-22E, or equivalent spark plugs from another manufacturer. This engine requires a spark plug gap of between 0.052 and 0.056 inch. Because the 4.6-liter engine requires platinum-tipped spark plugs, do not attempt to adjust the gap on any incorrectly gapped plugs. Attempting to adjust the gap may damage the platinum coating on the tip of the plug, resulting in poor performance.
