I got a misfire on the first cylinder code. I changed the first 3 fuel injectors. Still misfiring sometimes. I’d like to change the other 3 injectors for cyclinders 4 through 6 but Im not sure where they are located. Are they under the plenum?

 

Yes they are, have to take upper intake off

 

The misfire was caused by a bad ignition coil, which I replaced. It's running better than ever now. I worry about having 3 new injectors competing with 3 old ones. Do you recommend replacing the other 3 fuel injectors even though it's running fine?

 

No, they will be fine

The computer monitors lean/rich exhaust on the fly and adjusts injectors accordingly, so as long as they are the same pounds per hour there will be no problems