VW Polo 1.0l MPI misfire, probable cause ?

[Nathen]

just bought a y reg polo for my fiancee so she can learn to drive, and it's developed a misfire, Foxwell diagnostic kit showed it to be cylinder one, I've just served the car so I know it's not the spark plugs, any common problems with the engine that could be causing the misfire ? I know these engine do suffer with misfire issues thanks in advance could really do with some advice.

Sent from my SM-G935F using Tapatalk