The spark plug boots pull off (it usually takes a good hard constant pull, do not yank). Just make sure you pull the BOOT, not the wire. sometimes rotating them back and forth helps. Or, you could by a plug wire boot puller (pretty cheap, but not usually necessary). Only do one at a time, unless you have a friend who is a mechanic and can figure out top-dead-center and firing rotation.
It can be complicacated since on some models the spark plugs are difficult to get to but I would recommend to find the spark plugs first and then double check to make sure you know where they are.
factory recomends every 30,000 miles or 60,000 if you are running platinum plugs.
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/
They are under the ignition coils. 5/8" socket and 8 " extension.
Where are the spark plugs on a 1996 Nissan maxima?"
How do you install spark plugs on a 96 nissan maxima?
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.
6 spark plugs
6 spark plugs
Discovered fuel pump is running but there is no spark to the plugs. What now?
You can find the spark plugs for your 2002 Nissan Pathfinder on each side of the engine. The spark plugs will be near the top of the engine. A six-cylinder engine will have three spark plugs on each side.
Nissan 18L can you put super4 spark plugs