Jeep Patriot 2009/59 Reg CRD Limited Problems, any advice would be great.?

I have the Jeep Patriot in the UK its the CRD Limited model, Ive noticed that when in 3rd gear (its a manual BTW) when the revs get to around 2000rpm when easing off the pedal the engine kid of judders every now and again as if im in too high a gear for the speed im going but dropping down to 2nd would be too low a gear for speed, its as if something is struggling to get thru in the engine be it fuel injectors or oil but this is a reularity with the Jeep, I love the car but its driving me crazy every time it judders, its the same when you start it up the initial start up and the engine feels to rock quite a bit for a second or two but I think this is normal, any help would be great.