Rough idle and engine cuts off

Hi guys
My symptoms are, I start my freelander td4 auto car fires up no problem at all. But soon after that the rev counter neddle starts bobbing between 500 revs and 800 you can feel the engine dip and almost stall but the come back. So I put the car into drive with foot on the brake and pull away drive for a while sometimes minutes some times over an hour. The car is fine at speed the problem starts when slowing down and stopping, while stopped with foot in the brake the revs dip and go up a few times then the car will stall all this happens while the car is in drive but stopped it will also happen when creeping forward with no accelerator input. I have removed the egr cleaned and replaced it (its been blanked) I've removed the sensor that sits in the air pipe running across the front of the engine cleaned and replaced it I've disconnected the MAF sensor and driven the car now this initially made a difference idle was still a little rough but the car would no longer dip and stall at idle in drive with foot on brake but after a day the car is doing the same thing as it was before I did the above mentioned. I've ordered all the filters for service including the pcv mod just waiting for those to arrive but I would like to know what is the likely cause(s) for these symptoms oh PS I've ran some injector cleaner through the fuel system as well. Any advice greatly appreciated.

Do you know if your low pressure pump is working reliably?

I can hear it priming other than that I don't know if it's functioning correctly or not, how would I test it.

I would suspect the LP pump too. A failing one might be very noisy on prime, but otherwise you'd need a diagnostic plug-in to monitor fuel pressure.

I would go with injector issue.
First thing to look at is the loom on all four injectors, remove the loom cover with the three bolts, replace left bolt with cover off and start the engine, you need to replace that bolt otherwise oil will spit from the hole. Once engine is running (and hopefully roughly) in turn push down on each connector to make sure they are on properly, if engine then runs smoothly on any of them, problem solved and a cable tie maybe the answer.
But.
If after doing this it has made no difference then I would then get the Freelander diagnosed, this will both confirm if there is an injector fault and also which one. If the fault is intermittent the diagnostic will show the injector fault code as a previous fault until its cleared to.