You can find a spark plug wiring diagram for a 1998 Jeep Cherokee in the vehicle owner's manual. You can also find the diagram at various auto stores.
1998 Jeep Cherokee 2WD 4.0L MFI 6cylThe Spark Plug Gap.035 (In thousandths of an inch)
.044
.312 centimeters
awsf32pp motorcraft
.040
0.9 mm / .035 inch owners manual
I was looking at the 1998 Mercury Villager Owner Guide ( and one of the Ford websites ) and they both show the spark plug gap as ( .034 inch )
Spark plug knock on a 1998 Chevrolet pickup is an indicator that the ignition timing is correct. By adjusting the timing, the knock can be eliminated.
The factory plug or OEM plug recomended by Honda is a NGK CR9EH-9. For the 1998 Honda CBR 600 F3.
That's not really what's going on. The coil makes the spark, the distributor distributes the spark to the correct plug. If the distributor is not in the correct position, the spark does not go to the correct plug, or goes to the correct plug at the wrong time.
On a 1998 Lincoln Continental : Check the Vehicle Emissions Control Information ( VECI ) decal located in the front of your engine compartment ( it will show the type of spark plugs to use and the spark plug gap )