Possibly a sticking turbo veritable vane control mechanism? With engine cool and off, spray the control rod and mechanism down with some WD-40 or like penetrating oil, then manually exercise the control rod up and down and see if you feel any sticking points.
You may want to pull the air box and inlet hose to the turbo so you can watch the turbo vane movement while doing this?
I would also check all associated hoses, plastic tubing on this system for any vacuum leaks.

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Supporting Vendor and Moderator of LOST05 Jeep Liberty CRD Limited 
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