Running a bit rough. Doesn't stall, but when stepping on the gas it will sputter on 2001 Mazda B3000

Check engine light comes on. Got that checked. Code meant a problem with #3 cylinder. Replaced that spark plug and got a new set of wires put in. Yet the sputtering remains. Not sure what to try next. Even check the air in-flow and it looks clean. What do you think?

2 answers 1 comment
What did the spark plug that you replaced look like? That info would help point a direction , if indeed it was a problem (presume DTC P0303).
The spark plug looked used\ slightly blacken.
possible injector?