I have this code pop up. Spark plugs look fine but I decided to replace them all while I was in there. Reset ecu. Drove a bit and the code came back. What is the problem?

 

The weird problem is that it doesn't feel like an engine misfire. Car drives perfectly normal.

 

you can try to swap a coil pack with another cylinder. Then drive it for a little bit and see if the code moves to a different cylinder. It may just be misfiring once or twice under a no load situation and you may not feel it.