G’day everyone, New to the forum but I’ve been on heaps to find fixes for small little issues here and there. I’ve search google a bit but I’ve had nothing quite similar to what I’m experiencing

I’ve got a 2003 L322 with the TD6 engine. Seems to start fine and idle fine, but once warm when I come up to a set of lights it’s got a rough idle / feels like a lumpy cam. Revs fluctuate and you can feel it through the whole car. Once driving again it seems back to normal until you come to another set of lights to idle.

Also driving on the highway at 100km/hr there is a distinctive vibration only under acceleration or just coasting lighting on the throttle. With no throttle input it seems smooth as

Any suggestions on what to look for/ look at? No engine light on so I’m not sure if a scanner will find any stored or current faults

Thanks in advance

If you come to a standstill at the lights, what happens if you select neutral?
If the rough running disappears in neutral, my money would turn to the torque converter.
Could also be something like a propshaft bearing especially on the move.

Hope this helps & please let us know what happens…..we’re a nosey lot on here!  2012 Orkney Grey Westminster 4.4TDV8 with Ivory interior.........nice!
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Faulty injector or injector loom? 1st easy check, with the engine running and tick over lumpy as you describe, remove the plug from each injector one at a time, if it gets worse replace the plug and move on, if there is no change investigate that injector. I the loom or plug is in question wiggling it might get a smooth idle temporarily. Shame you are on the other side of Oz, I have a good loom and injector here 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone