C13 acert misfiring cyclinder 3 & 4

It happens. I've had #2 and #3 go out at the same time. The shop tested the injectors, said they were fine, replaced the wiring harness and ECM, then went back and tested the injectors and they both failed. I think there's a way to swap the injector plugs so you can see if the problem is with the wiring or the injector, but I'm not sure if it has to be done in a certain order.

If the injectors are the problem, I'd probably get all 6 replaced.

 

Probably injector ground wire. I think cylinder pairs share a common ground in the harness.

 

Well for starters Cat engines don’t set misfire codes. They don’t even monitor engine miss.

You may have multiple injector fault codes that are causing a miss, but your assumptions are correct. It is unlikely to have 2 fuel injectors fail at the same time.

 

It is most likely your IVA solenoids or the housing.