They are numbered 1-2-3-4-5-6 front to back.
Number one spark plug is closest to the radiator.
The spark plug gap for the 1994 Jeep Grand Cherokee 5.2L (318CID V8 is .035".
I believe you have to buy a whole new coil rail.
the 4.0 six in a 90 jeep Cherokee is not a v6 it is an inline 6. the firing order is 153624
It can be done, but it won't be a simple "plug and play" swap.
.034
1998 Jeep Cherokee 2WD 4.0L MFI 6cylThe Spark Plug Gap.035 (In thousandths of an inch)
.035
.035".
On the v 8 it is the front driver side cylinder.
check the spark plug wires and the distributor cap wires
The fill plug is on the center of the rear of the transfer case.