Mk3 Tdci 130. How Long Can It Last With Injectors That Cut Out?

I known you've seen the cutting out topic a thousand times, but please bear with me lol.

Couple of months ago the car cut out when i dropped to 4th at 60mph to overtake a lorry, power kicked in then litrally bang, loss of power then a few hundred yards i was holding up fast lane traffic coming to a stop lol. Started back up and got to where i wanted fine. I reckon a week up to that, the car started chucking out more black smoke, so seems like injectors.

Basically in 4th gear upwards, if im at 2500rpm and floor it , just before it reaches 3 the car will cut out. But i came to actually find the car is fine if i stay below 2500rpm, for a to b its still ok.

I serviced it myself yesterday (finished today), just waiting for my current tank to nearly empty and add some bg244. Took it for a run, feels smoother but in the higher gears would still cut out. But 1st to 3rd are back to how it was before the cutting out started, they had gone sluggish slightly, the black smoke has gone right down now as well.

Now im not expecting the bg244 to fix it, my main question is, how long will the car be ok under 2500rpm, on what i think must be the injectors? To be honest, its all you need to drive within the speed limit.

The car owes me nothing, purchased in 2013 for £1200, only thing thats gone wrong and been replaced is starter motor, passed its mot's with flying colours. I'm In the process of trying to save for a deposit on a house and a deposit on a newer car, so i want to run this in the ground for as long as possible, the car is on 169,950 miles currently.

If it lasts 6 months that will be ideal, a year perfect lol. Anyone know the answer or give a rough estimate.

PS: I cleaned the egr valve while servicing the car, so the cutting out isnt that. Also has the grey cam shaft sensor already fitted, i know the original black 1's caused cutting out