All 5 injectors are different. When they are produced they are tested. The codes are "tolerances" that ensures that the injectors perform equal.
I would be worried if they where the same.
In 1.9JTDM codes were printed on each injector, so you can check they are the same (verify the order if e.g. they were taken away during maintanence work of the engine). I heard that only if you get your injector to some repair/refurbisshing, they may test them on machine and issue new calibration codes, and not necessarily re-print them on the injectors, so difference vs what is printed with what sits in ECU may mean wrong or not necessarily if new code was assigned.
Anyway, +-1 corrections are quite good, +-2 I thnk it is acceptable range.
Ok that worrying i am averaging 216km i think something is wrong if you get 600miles. The injectors do add up to 0 so that is good and the egr has been stripped and cleaned. So has the maf, map and lambda sensor
So what next ? force a regen to give it a proper clean out?
No, do not do forced regenration - it usually makes more bad than good.
216km average DPF regeneration sounds to me very wrong/short. Not sure how ECU counts interrupted regenerations, maybe it is just that causing low average - I do not know. But still, even interrupted, they woudl do oil degradation each time (bit of fuel gets into oil during regeneration) - so with your poor avererage I guess your oil may be done after say 3k maybe 5k km.
My former 159 1.9JTDM 16V had average distance of 700-1200km between regenerations. It was driven mostly in town, on short distances from cold start, once/twice a week 20km run on motorway one way, and return a few hours later (visit parents), and for 7 years it never had any DPF issue (of what last 4 years driven with EGR blanked and ECU mod).
Yeah i do a lot of short journeys so that might be one reason but I have made a discovery .
I just did a forced regen to see what happened. It all seamed to go ok but after The pressure differential was -5 and the clogging was 68% surely this can be right strait after a forced regen. What dose this mean what is the best was to de-clog the dpf without damaging it?
God, why you did that forced regeneration? It is not neutral to your DPF as far as I read various posts on forums - this procedure is meant for extremely clogged DPFs, where there is serious issue, as kind of last chance to make the car drivable (where it does not drive because DPF is so much clogged). I heard that with healty DPF it rather partially wrecks it - it is never the same good again.
And, after forced DPF regeneration, I read you need to change your engine oil, as the procedure is much worse than standard DPF regeneration (which also degrades oil but way less).
Forced regeneration is also risky - cars can burn (during normal regeneration there is air flow, which cools down exhaust pipes, car floor etc, but while steady you do not have that). Exhaust temperature then is someting like 650C deg or someting.