Plug gap is .040"
No, that's an indication of a problem.
The spark plugs in this car are on the side of the engine. They are seen after the engine cover is removed.
The firing order for a 1991 Isuzu Trooper 2.8 liter 6-cylinder is 1, 2, 3, 4, 5, 6. The spark plug gap is .045 (in thousandths of an inch).
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 )
.6 mm on all 2003 gmc model trucks according to my manual
.044 for a 1997 model
I believe that it's just above the Front Right spark plug coil. It has a vacuum hose attached to it.
should be .035