Toyota Repair: Engine misses then runs fine, vacuum leak, dtcs

Question
I have a 2000 Tacoma with a v6 3.4L. When it is cold it runs fine but when it warms up it misses and lopes. Both at idle and at speed. The check engine light will come on then go off. The codes I've gotten are 300 and 301. I can't find a vacuum leak and I've replaced the following. Spark plugs and wires and the fuel filter. I've added fuel injector cleaner to my gas as well as a gas treatment to see I had water in my fuel. I give up! What should I do next? O2 sensor? Egr valve? Thanks for your help this is driving me nuts!

Answer
There are two possible and common causes for this, the #1 fuel injector or the #1 ignition coil pack, clear the DTCs then switch the #1 coilpack with #3 then drive it until the check engine light comes back, check for DTCs and see if the misfire now moved to #3 (p0303)if it did replace the coil. If it does not then I would recommend replacing the #1 fuel injector.