Changing the spark plugs on 2003 altima 2.5L

Not that simple on newer cars, but you do still need those tools.

Here is a good write-up: Changing Plugs on an Altima that will show you the location of the coil packs that must be removed first (9th picture from the bottom) and what they look like.

Doesn't really need to be done until about the 100,000 mile mark. Do not do it while the engine is hot or even warm. Replace with the factory recommended spark plug. Place a little anti-seize on the threads and some dielectric grease on the top. Be sure you torque them down to the proper setting. I believe it is somewhere around 20 ft. lbs., but if you call the Nissan service desk they should be able to tell you for sure.