Fault code help for misfire

[williams]

Hi everyone, looking for help with a misfire that developed yesterday. Plugged a code reader into it tonight at a friends house and it came back saying "injector circuit open cylinder 4" and "single cylinder misfire (cylinder not specified)". Does anyone know what these codes suggest the fault relates to and could it be wiring or a faulty injector on cylinder 4?

thanks in advance!

Codes shown here too

 

[Big hyndy]

I just bought a 172 with the same fault, injector 1 open circuit. Swapped injector 1 to 3 and plugged it in again and it came up injector 3 open circuit. This confirms it's a faulty injector. Your best trying this first to see if it is the injector to blame.

 

[MarcB]

Im going to suggest the most common problems which are

Coil Pack
HT Leads
Spark Plug
Injector