Misfire at low rpm

I have a 1999 prerunner 3.4 L V-6 automatic. Its been giving me a P0303 trouble code #3 cylinder misfire. Changed spark plugs, leads and swap coil pack with #5 cylinder and the problem is still on the #3 cylinder P0303 . I also changed fuel filter cleaned Mas airflow sensor. It appears that the problem is more noticeable at low rpm (vibration) at higher rpm very little vibration.

 

Same problem. bump.

 

Sounds like you have covered almost everything you might have a bad injector or worst case a valve problem.

 

Thanks for the reply. I went ahead and changed the injector on the #3 cylinder and problem resolved. One note to add is before I replaced it I checked the resistance on it and it was normal 15 ohms. Manual calls for 12 to 16 ohms.
Not really sure if resistance changes when truck heats up or maybe a partially clogged injector.