Non Land rover engine diesel problem

Hi I am having problems with my Citroen dispatch van, it is 2.0 hdi common rail engine, I was getting it ready for its pollution test and had put some injector cleaner in and was driving it just a bit harder than normal.
I was going up a hill when I lost a lot of power, got it home, engine looked like it was running on 3 cylinders I took off a injector electric connector from number 2 cylinder (as have had problems with connector on it before) and engine did not change so thought injector had a problem, changed it for another spare I had but no better; cutting the story down a bit took all the injectors out re-seated them fitted new copper washers bought a good recon injector fitted it in cylinder 3 same problem,
took the connector off 2 and 3 engine still run the same but the injectors seem to work when I rev the engine, took it for a drive and not 100% but can drive it no problem
Checked fuel rail pressure should be 290 bar at tick over but was only 250 so took off fuel pressure regulator cleaned it and now have the 290 bar but still ticks over like ****, tried using it for work today works okay did about 100 miles but still not any better

Compression test?

AllanWorms said:

Compression test?

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might be but drives okay and was working okay one minute and then not the next on 2 cylinders, think next step is to swap the new injector into cylinder 1 or 4 as they are working and see what happens I am away for a bit so stopped using it, it is putting some diesel down into the oil.
Also starts really easy first turn of the key straight away as if when there is a bit more pressure the 2 injectors work but then just runs on 2 cylinder until a bit more revs