Po306 code problem

I have checked the plug, plug wire, swapped coil pack and installed new fuel injector and still get po306 code. When engine is cold it runs fines and then about a mile later starts missing and brief check engine light flashing. Truck is my nieces and has 284 thousand on it. I am trying to keep it running until she can save enough for a newer truck. I am out of ideas. Any help would be appreciated.

 

What year is the truck?

 

2002 prerunner

 

Try over- https://www.tacomaworld.com/forums/1st-gen-tacomas-1995-2004.4/
That’s a link to the 1st Gen forum. That’s what your truck is. Those guys have a lot more knowledge and experience with your 3.4 engine.

This the 2nd Gen forum. Our trucks have the 4.0 engine.