TD4 'chugging'

After a bit of advice on diagnosing a fault guys.
Today my wifes FL1 TD4 started chugging/vibrating when idling. Not effecting the driving at all but when stopping at lights etc you can feel the chugging / vibration and hear it in the engine note. It sounds as though its not firing on all cylinders but the idle is steady and doesnt fluctuate?
I have the fuel filter to change anyway tomorrow so im hoping it might be the cause but id have thought a fuelling issue would cause the idle to fluctuate as well which it isnt

leaking injector maybe, worth doing a leak back test, also check wiring for security on the battery etc

Injector was what I was thinking but hoping its not. Suppose id better try and get it booked into a garage to get it checked

Is it off a cylinder? if not could be crank damper pully.

Not sure what you mean by is it off a cylinder?
I dont think its any kind of damper or engine mount issue as you can hear the chugging in the exhaust note. Almost like its not firing on all cylinders (is that what you meant?)

Get it chugging and unplug the injectors one by one. The injector that doesn’t affect the idle speed is the dodgy one.

Sounds like a plan. Ill give that a go.

Is changing an injector a DIY job or does it need specialist tools?

It is a diy job unless they are really stuck in, and when tightening back up by careful because the small studs 1either side can break and from lr they are expensive the last time I purchased one which was about 8 years ago was £26 plus the vat ,

Well i changed the fuel filter today and unfortunatly no change.

The bit thats putting doubt in my mind is wouldnt the revs fluctuate if it was a duff injector and misfiring?

The revs are completely rock steady and the car drives great but the whole car is now shaking when its stationary. You can actually feel yourself bouncing in the seat!

There are a couple of suggestions here.
https://www.landyzone.co.uk/land-rover/rough-idle-vibrating-on-td4.93095/
A quick Google would suggest it's not that unusual.

I just had a thought, it could be a bad connection or broken wire that is worse when idle because the engine rpm is lower. If it is you would expect the problem to get worse over time.

Already changed the fuel pressure overlay wiring harness so definatly not that. No issues with idling or staring just seems to be missing a beat and shaking the whole car

Gonna unplug the injectors one by one as advised tomorrow and will report back

Well unplugged each injector today and looks like one of them is knackered
3 of them made the idle stumble when unplugged but one of them had no effect when unplugged.
Time to source a new injector!

On the plus side though I changed the glow plugs. Scariest plug change ive ever done. All 4 where really tight and I was convinced I was going to snap one but with the help of about half a can of plus gas they all eventually came out and its now starting on the button

Glad to say a bottle of injector cleaner and a 200 mile trip seem to have sorted out the issue and its now running great