TD4 multiple injector failure?

My TD4 has been running badly last few weeks, missing a bit at first, then losing power gradually over a journey until it struggles on hills - it eventually gives up. Just had a diagnostic check done by local indy and it shows 3 injectors have failed....is it realistic that 3 could fail like this....? 2 have been replaced in last 3 years, planning to get fixed and sell, but wonder if it might be worth getting second opinion?

have you just been using regular diesel or trying bio or additives to clean injectors?
If you have tried fuel additives, it can carry gunk out of the tank in bulk, multiple failures becomes easy.

Thanks for that. No, have just been using regular diesel. I just find it odd that the car is still 'drivable' (to a point) whilst 3 injectors are down.

Diesels are like that, they will still fire with faulty injectors, just not as efficiently. Some engines don't regulate air intake, only fuel flow rate to regulate power.
If 3 are faulty you might as well do 4 to balance things up properly.

I had 2 faulty injectors diagnosed by my local Indy, but in the end it was only one. A quick check is to unplug each injector in turn with the engine idling. It's amazing the difference just one dodgy injector can make. A failing low pressure fuel pump can cause loss of power…