Are those coils still good?

My dad's car is hesitating when using the gas engine, the electric motor is smooth but the gas engine is acting like maybe some spark plugs have gone bad. We worked on his car a couple months ago, last April replacing all the denso spark plugs to some ngk's.

Today, we decided to check his spark plugs to see if there's anything wrong but those coils are looking a bit weird and the ngk spark plug seems ok.