According to one of Fords websites :
For a 1986 Ford E-150 ( 4.9 / 5.0 / 5.8 )
( .044 inch spark plug gap )
* unless it is the 4.9 / 300 cubic inch inline six cylinder with High Altitude Calibration , that's .054 inch
.044 inch
6 spark plugs
Yes , the 4.6 liter V8 engine in a 1999 Ford E-150 has ( 8 spark plugs )
According to one of the Ford websites : For a 1986 Ford E-150 : Both the 5.0 / 302 cubic inch and the 5.8 / 351 cubic inch V8 engines have the spark plugs gapped at ( .044 inch )
which engine?
In a Ford 5.4 litre V8 engine : ( there are 8 spark plugs )
in the heads
6.
According to motorcraft.com , a 1994 F-150 , 5.0 L - V8 engine spark plugs are gapped at ( .054 inch )
You will need to remove the engine shroud from inside the cabin to access the engine and plugs.
Motorcraft Platinum Plugs.
Check the Vehicle Emissions Control Information ( VECI ) decal located in the front of the engine compartment ( it will show what type of spark plugs to use and the spark plug gap )