P0306 on a 98 4 runner

1998 Toyota 4 runner w/ v6. Truck started dopping a cylider at idle. I hooked up my scanner (wich I havent learned how to use yet) and got this code. Says its misfiring on cyl 6. The truck runs perfect when cold, but when it warms up it starts misfiring. I need to get a service manual for it and fix the issue, but was wondering if i could get some help here and pointed in the right dirrection. Thanks in advacnce for any help provided.
I have minimal diagnostic tools. Scanner, fluke meter, and hand tools.
Thanks again!

what about a tune-up?

Seemed to simple .
Will do tonight. Repost tomorrow.

Well I swapped out the plugs and it has the same problem. I also swapped out the coil on #6 with another cylinder, ran it, and noticed it was still missfiring on cyl6. So I used the scanner in Check mode and drove the truck. I noticed that the misfire went away when accelerating (moderatley or heavy) but when coasting the misfire counter started going. 99% of the time it was cyl6 with a very occasional misfire in cyl5.
When the vehicle is in park or neutral, the misfire steadily becomes worse. On a free rev in neutral the misfire is still there. Mainly under a load I can get it to stop. The MIL also comes on with codes P0300 and P0306. What would you check next? Thanks in advance for any info, This site is great!

Suggestion: Try some fundamentals as well as poking around with the diagnostic scanner(s). You mentioned misfires go up as engine idles, or slight accelleration. Sounds like to me, Cyl 6 may have low compression (leaky valve or worn cylinder). Compression PSI goes up with increased RPM because air has less time to escape from a possible leaking point. Cylinder will fire better with good compression than with low comp. Any water in the oil...oil looks milky in color? Blown Head Gasket. Otherwise, good luck with your diagnostics. Remember, though... The Scanner is not a tell-all. Old-Fashioned poking around is still required in all successful diagnostics. Oh... and if you have a vacuum gauge, hook it up to the intake manifold. It's a wonderful (sometimes forgotten) device which supplements diagnostics such as in your case.

Problem went away completely for about two days without touching a thing. How wierd. Now its back. Same cylinder. I pulled the plug after letting it idle with the missfire for about 15 minutes. Plug looks perfect. Hard to believe its a compression issue with it being an intermitent problem. I will have to do a compression check next I supose. How about a fuel injector issue?? Is that possible? Anyone else with this simular problem? thanks.

Check the plug wires (resistance and water spray test).

yeah Try a set of wires

I did an ohms test and came up with like 17.something and the wire is like 3'. I tested the one next to it and came up with 13 I think. So I swaped the wire with the cylinder next to it to see if the miss changed to the next cylinder and it did'nt. Could it be two bad wires?
How do you do the water test?
Also, I noticed that its the last cylinder in the feed of the fuel injecters. Could it be a fuel filter? Does the fuel preasure change as the engine load goes up? I know Im searching here but this is a wierd one to me. Thanks again!

I am headed to Napa now to get wires and a fuel filter. Thanks guys!
Will let you know how its works out.

We suggest you get dealer wires as aftermarket parts quality are often suspect.

Water spray test: Mist the wires with a spray bottle in the dark. Look and listen for arcing.

Good luck and keep us posted.

do a compression test while you're at it!

Thanks guys. I will pick up a compression tester kit too.

Compression is 175lbs in cylinder #6. (as well as all the way down the line) whew.

and what about the wires? Is the injector on cylinder #6 pulsing? Try switching the injector from any other cylinder that's not misfirng to #6