Cant find the spark plug location on 2002 4cyl tacoma

check compression, check valve clearance, check injector for properly working, check for vacuum leak around this cylinder.

Obtain a Hayne's Repair Manual. They go over spark plug replacement.

Possible causes for a misfire:
Spark plug
Spark plug wires
Weak or bad coil
Dirty or a bad fuel injector
Low compression in cylinder
This is a case of testing and process of elimination. Have them all tested to find out which one is the culprit. Change the plug and wire to a different cylinder, if the misfire happens in that cylinder, you'll know it's either the plug or the wire. Without doing any testing, it's hard to say what the cause is.

Changing the spark plugs is a pretty easy task. The spark plugs run along both sides of the engine, 1 per cylinder. (3 on each side) You can easily identify them by the plug wires running to them from the distributor. Pop off each plug wire, (1 at a time) and replace the spark plug. Once you have replaced the plug, replace the plug wire. This ensures that you dont mess up the sequence of the wires which determines which cylinder fires at what time in the cycle. VERY important not to mess up the sequence. If you should happen to get the wires mixed up, look online for the firing sequence for your vehicle and engine.

you have to remove the four ignition coils from the top of the valve cover and the plugs are down a hole underneath..

You didn't specify whether you have the (4) cylinder or the (6) cylinder engine..... I have a 2004 Hyundai Sonata 2.4L 4 cylinder and I just changed the spark plugs in it. I believe that the 2005 2.4L engine is the same. To locate and change the (4) spark plugs on a 2004 Hyundai 2.4L 4 cylinder engine: Remove the (4) 12mm bolts from the decorative plastic engine cover. Remove plastic cover from engine and place it off to the side out of your way. Standing in front of the car, the (4) spark plugs are located laterally (left to right) in the recessed area underneath where the plastic engine cover was removed. Note: This engine has (2) coils....They are located above spark plugs number (2) and (3) from left to right. Starting with the fist spark plug on the left: Remove the spark plug cable by pulling straight up on the insulated connector. Using a spark plug socket, remove the old spark plug and install a new one in it's place. To access the second spark plug from the left, remove the electrical connector and the spark plug cable wire from coil number (1) and then remove the (2) 12mm bolts that secure the coil to the engine. Spark plug number (2) is located directly under the coil. Lift the coil straight up removing the insulated connector from spark plug number (2). Using a spark plug socket, remove old spark and install a new one in it's place. Repeat same procedures for spark plugs number (3) and (4). Note: If you have the (6) cylinder engine, the front (3) sparks pluge are readilly accessible but in order to access the (3) rear spark plugs, you will have to remove the intake manifold

bring it to a garage

the spark plugs are under the coil pack which is bolted on with one bolt on top of the valve covers with one wire plug going in to it there should be 3 on one side

24 mpg on the highway is actually pretty good for that truck. at 48000 miles and being 3 years old its time for plugs, air filter, and fuel filter if available. thats cheap maintenance for now. but if very self conscious, run some fuel injector cleaner first, then change the plugs, because any octane booster or fuel injector cleaner can run the risk of fouling out a plug, by creating a hotter spark then what, normal gas does. the burn is hotter.

P-0304 indicates number 4 cylinder misfire. Are you using Toyota parts dept spark plugs? More often than not, non-toyota plugs make the v-6s run poor, right out of the box....
Try this:With the engine running, pull the connector wire off of the #4 injector. Note to see if there is any change with the idle quality. No change? You may have a bad injector.