Freelander 1 [2.0 TD4] jerky engine after fuel filter replacement

Hi,
I replaced the fuel filter on Saturday, it worked fine on my way home from garage (the second time, the first was a nightmare but I'll describe it in separate topic as a warning...)

Didn't use the car over Sunday, this afternoon when I started it I could feel that it works strange, I could feel short brakes/jerks.
Revs are not constant, it drops a bit if I keep it on the same level.

I did the tests on the parking spot, I didn't want to risk driving it in case it stops somewhere on the way.

Any ideas?

Are the connections to the LP pump okay? When I changed the filter on mine a few weeks ago the pump connections didn't look the best. When I refitted the assembly the pump didn't prime. I had to take it all out again and clean up the terminals. I'm half expecting it to go intermittent at any time but I've done nearly 3k miles since and it's been okay. Might be worth a check.

I checked them when fitting filter but didn't disconnect and connect again, only the electrical plug as it was on the way.
I don't have a time to put it apart at the moment.

I started it this morning hoping it fixed it self over night
I noticed that I can feel engine jerking only on high revs, when it's idle it's calm. There also was a lot of white smoke from the exhaust pipe for quite a time.
I gave it a ride around the estate, while driving I couldn't feel this.
When the engine heat up I couldn't feel it any more even on high revs while parking. Only just a bit every so often but not as much as on cold.