Freelander 2 (LR2) Hiccups on Idle and Exhaust Fumes

Hi all,

First post on the landyzone forum! I've recently purchased a Freelander 2 2011 2.2 SD4 and I'm experiencing hiccups on idle. The revs rhymically drop from around 1000rpm to 750rpm and back up, repeatedly whilst I'm stopped at lights/in traffic etc. Occasionally, I've felt it might stall. Combined with that issue, when stopped, I'm also smelling exhaust fumes in the cabin (appreciate this might be unrelated). Both issues do not present when driving and it otherwise runs well.
Had the EGR valve out over the weekend, it wasn't that caked. Cleaned it up but the issues are still present. Found small leak on EGR valve to cooler, thought that might be the cause of the exhaust fumes but replaced the gasket and the fumes are still happening. EGR valve and cooler were both replaced 20,000 miles ago by previous owner.

Any advice would be greatly appreciated!!

First test is to put the climate control into ECO mode, or off completely. This will turn off the AC compressor, which does put a rhythmic varying load on the engine. If it's still doing it, then really it needs to have all the live data values graphed, which can help find the cause.
The most likely cause is a sticking or failing throttle body.
A blocking DPF can also cause strange faults, and a failed exhaust pressure sensor pipe can create an exhaust smell.

What miles are on it, and what sort of driving does it do?