The electrical valve I changed out, 11747796634, sits under the inlet manifold and is at the other end of the vacuum hose that attaches to the EGR diaphragm housing. As Evo said, daft place to put it.

Evo1, your a star. Had same 3-4 second acceleration lag on '07 X3 3.0d slowly getting worse over the last month. Particularly bad after slowing right down or stopping then trying to accelerate. Main dealer took off inlet manifold, replaced MAF sensor but no improvement so buttoned it back up said ...