Freelander TD4 engine component

Hi, Have had intermittent starting problems with my 2006 model, have eliminated the MAF, and cleaned the engine crankcase breather valve but find clean oil moving though the air inlet manifold into the unit Front left side of engine Cylinder shape about 2 1/2" dia x 3" long (see picture). The sensor in this unit then becomes contaminated and makes starting problematic, (hot stating in particular)> cleaning this unit solves the problem. I'm told there are no fault codes showing. Quick solution to me is to repace the dirty sensor unit but its diffult to buy if you dont know what is called or what its function is ( might be a temperature or flow sensor.
Grateful for any help on this: