Working from passenger side, snake your left hand between firewall and engine until you feel the plug. From this position you can lower tools to remove and replace plug. This trick cost me $30 at a local garage.
PARK PLUG GAP1999 Nissan/Datsun Truck Frontier Pickup 2WD 2.4L SFI 4cylThe Spark Plug Gap.044 (In thousandths of an inch) SPARK PLUG GAP1999 Nissan/Datsun Truck Frontier Pickup 2WD 3.3L SFI 6cylThe Spark Plug Gap.044 (In thousandths of an inch)
2000 Nissan/Datsun Truck Frontier Pickup 2WD 2.4L SFI 4cylThe Spark Plug Gap.044 (In thousandths of an inch)
2003 Nissan/Datsun Truck Frontier Pickup2WD 2.4L SFI 4cyl/2WD3.3L SFI 6cylThe Spark Plug Gap.044 (In thousandths of an inch)
.o39 to .043 inch
0.039 in.
The Nissan frontier would most likely have their spark plugs down deeper into separate chambers. If it is anything like new ford model trucks you have to locate the wires covering them, about an 8 in extention and a 5/8 in spark plug socket.
All 4 are on the motor.
They are under the ignition coils. 5/8" socket and 8 " extension.
your piston rings might be bad
This is for the '05 Frontier, but should be what you're looking for. http://www.clubfrontier.org/forums/f23/how-change-spark-plugs-2005-gen-2-frontier-40507/
The 1998 Nissan Owners Manual for the vehicle says, 0.039" to 0.043" or 1mm to 1.1mm.
factory recomends every 30,000 miles or 60,000 if you are running platinum plugs.