Injectors are blamed quickly because they are familiar. Sometimes they are the fault. Often they are the result of dirty fuel or low pressure. A short test saves a full set.
In the workshop
- Cut out cylinders one at a time and listen for the one that does not change
- Check return flow where the system allows it
- Look for fuel dilution in the oil
- Replace filters and confirm pressure before the new injectors are fitted
- Load trim codes if that engine uses them
Handle new injectors clean. A single grain in a common-rail seat is enough to ruin the job. Cap the lines while the rail is open.
Order by the number on the body and the engine serial, not by “same as the last 320.”