Pretty sure I've got one....
I've followed the sticky guide and checked block 32
Read values 1.7 & -2.3 with fault
16891/P0507/001287 - Idle Control System RPM: Higher than Expected.
(I've also been flagging 16885 so looks like vehicle speed sensor is dead but I don't think it would do anything???)
Anyway cleared faults, and watched it sit steady at zero zero for a while till oil temp came up. Just as the temp needle starts to lift, the block 32 readings shift to 0.9 and -0.8
Went for a quick thrash (max pressure reading on 115 was 2.4 bar absolute - I make that ~20psi boost???). So boost side is ok?
Came back and sat at idle for a bit and watched the block 32 values rise up to 1.7 and -0.8.
So, my question is have I diagnosed this right as a vac leak? and if so where are the most likely culprit areas to check?
There still well within tolorence, maybe leave it a bit and look again, the first figure is idle adaptions so poss a vac leak..check fuel pressure reg piping and associated pipe work