All

Not been around much - had some personal issues on the go and really busy with work. I could do with some help please, I promise to be around a bit more!
The FF had (past tense) been largely trouble free - did 2500 miles to Italy and back, loved it.
Lately she's been intermittently idling like a right cow. Start up fine, if it's going to happen it will do so within 30 seconds. Lumpy idle, sometimes worse than others, if really bad she smokes terribly (black). So looks like a fuelling issue.
Initially thought it was hte right hand bank after watching exhausts as Mrs JB drove off.
Have connected my IID tool many many times over the last cpl of weeks. Occasionally had a restricted performance injector fault but not always the same injector. Looking at the live data for injector balancing its clear there is some mismatching - when the car smokes two injectors will show high readings, when lumpy just one. But it's not always the same injector - have had issues with number 3, 4, 5. All intermittent.
She's never run on supermarket fuel, only decent, and on our euro-jaunt did half of it on super diesel.
Threw some Millers injector cleaner through last week and went for a run - next day she ran good, then rubbish since. Today I've been dad taxi and done about an hour and a half in traffic, no trace of lumpiness. But it will be no surprise if she is terrible when I go out later on.
Been some odd codes here and there - the most regular one a P007f-62 charge air cooler correlation. This is not regular as in every time though. V occasional maf sensor code but on live data both give readings which increase on revving accordingly.
Just before I bought her the supplying dealer put her into a specialist for a similar lumpy idle fault - they replaced Injector 1.
I'm not one for changing parts in a try and see fashion - but am not exactly au-fait with the intricacies of the diagnostics here.
My mechanic is very logical and really good (hence using him) but again is not a specialist specialist on LR products (despite owning a defender and Disco 4).
Any hints or tips please? Would be appreciated - its the intermittent nature that is screwing things up.
Have loads of screenshots I can post up of data if req'd.

Also have some spurious electronickery faults coming up so a water-ingress search in the boot is my next job as of right now

TIA 2007 Vogue TDV8 with 255/55/20's fitted

Anyone had any thoughts on this? 2007 Vogue TDV8 with 255/55/20's fitted

Could possibly be the injector wiring loom?
or
many of your injectors have given up the ghost (try a leak test?), but this doesn't explain the smoking...

(Assuming this is a TD6, you haven't put car type in profile) .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999

Car is at bottom of my post Joe - tdv8. 2007 Vogue TDV8 with 255/55/20's fitted

Doh! Mine is next to my flag under my avatar  .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999