According to the Hanes Manual: .044
.044 inch ( for your 4.9 liter / 300 cubic inch straight 6 cylinder engine in a 1991 Ford truck , according to motorcraft.com )
The spark plug gap for 1987-1991 Toyota Camry: 2.0L, 4-Cylinder is 0.044.
Check the spark plug and the wire on the 8th spark cylinder. Corosion, short, or just bad.
passenger side of engine , front cylinder
1991 Jeep Cherokee 2WD 4.0L MFI 6cylThe Spark Plug Gap.035 (In thousandths of an inch)
The diagram.
.035 inch
www.motorcraft.com shows (.044 inch ) plug gap on the 1989 F150 300 cubic inch ( 4.9 L ) straight 6 cylinder engine
The spark plug gap is .054"
The spark plug gap is .054"
I think it's .035