Sticking injector pump??

[Zolate]

I have a 2002 2.4 diesel that has done only 17000
Kilometres since new. ( still has the original
Michelin tyres with good tread. Sidewalks a bit weathered.
The van starts, drives and accelerates well but has two problem areas.
1 ) there is a jerk (not the driver) when backin off the accelerator at cruiser sowed and then again
When accelerating again. Similar to like tailshaft slap.
2) the acceleration at very low speed ( like parking in a tight space) is very erratic.
From idle it is very hard to get a smooth increase in revs. It rather suddenly jumps.

The computer scan suggests there is s problem with the injector pump and someone has suggested
The fuel rack maybe sticking because the vehicle had sat around so much.

Does this sound feasible?

Do the symptoms match this scenario?

Is there a way to rectify this without spending three grand?

Any info greatly appreciated.
Thanks
Zolate