Vauxhall astra sxi 1.4 engine miss fire Error P0303 on tool

Vauxhall astra SXI 1.4 Error P0303 and miss fire on cylinder 3 So a new coil pack was needed do hope the injectors are OK as don't think I have tool to remove them will find cost and just buy it. all running OK car was in idle car engine jittered and cut off.