local 3.2L Sportero owner here
is yours auto or manual

2.5L or 3.2L

before you run off and buy a set of miracles in a bottle, please check the mechanical functionality of the vehicle (no offense to the powersellers)
that problem sounds like it is fuel or air related, a starvation upon opening the throttle - either air or fuel
clean filters (fuel and air) and sensors (MAF and fuel pressure) are the first checks, before buying any treatments
the vehicle is supposed to work normally with regular (no-additive) diesel and air.
get it working properly first and then consider additives to maintain proper working functionaliy
before you pull-off, if you revv the engine, are you getting a healthy idle and revv

if you revv a bit before pull-off then pull-off are you getting the bucking

if you want a good mech call 305-9900 (tell him Shawn with the 3.2L sent you)
a scan of the vehicle should also be arranged