Some guidance required please!

2010 Range Rover Sport 3.0 TDV6 HSE

I had both inlet manifolds and both EGR valves replaced last year after which the sun shone on my Rangey.

Recently, whilst on a long journey I got the restricted performance warning. As we were away, a local garage gave us the fault code P0488-72 intermittent. They did a road test with live date and the EGRs were both operating.

The fault code (and problem of restricted performance) remains and manifests itself after a bit of driving especially when the engine is required to pull a bit (up hill etc.)

Does anybody have advice on how to investigate a likely cause please?

Thanks in advance.

Sounds like time to check connectors and wiring for faulty grounds or bad connections. 2011 RRS HSE Luxury 3.0 TDV6 Fuji White on Ebony/Ivory
Born and raised in So Cal. Moved to the UK in 2018 for a few years. Now in Poland and looking at moving back to the UK.

Thanks for taking time to reply.

Should I focus on connectors and wiring relating to the EGRs?