Help please.. engine limp mode..

[Claymore]

Hi guys..
Any suggestions on the following would be graciously accepted..

Under hard acceleration my 3.0TDI is going into limp mode..
A typical example is pulling away from a roundabout with boot down hard, but not excessive RPM, or pushing on to overtake.
First thing I know that anything is wrong is the preheater plug flashing on the dash.. Not getting any other messages, no fault codes showing that appear related, and switching engine off and on again resets everything and back to normal..

I do however have my engine warning lamp on due to ongoing problem with bank 1 inlet manifold. Any ideas if the two could be related? Maybe something to do with the airflow control through the flaps? This has only started recently, but the manifold problem has been there since Nov/Dec.

Anybody seen theis before??