Apart from the anti- stall, the ECU has "eco" / fuel saving strategies, including fuel cutoff on the over-run/ when the throttle is "off" or "low"
There can also be a delay due to turbo-lag, the EGR system can interfere with the combustion process, causing flat-spots, which may cause your "shunting"
You dont say when the car was last serviced, a fresh air filter can help, this can improve power before the turbo boosts, thus reducing lag - this alone could eliminate the problem
A frequent fuel filter change is a good idea for these engines - a genuine Ford or "quality" filter (eg - Bosch) is important - cheap pattern ones/ some other makes can cause problems
A frequent oil/ filter change is good preventative medicine (when the mk3 diesel was ist released, recommended oil changes were 5k, then 6, then 10 - its always been (basically) the same engine since 2000 to 2007) - again, genuine Ford or "quality" filters "cheap" filters can cause problems/ "quality" oil can help the engine run smoother, more economically, and last longer
The EGR valve/ system contaminates the inlet manifold with carbon this can also mix with the oily droplets from the breather, creating an oily "goo" which builds up over time and can "choke" the manifold- reducing the air going into the engine - this needs to be cleaned out periodically - this should be part of the sevice schedule but is'nt - the inlet manifold should be taken off to clean it out, its a messy job
Blanking the EGR (exhaust gas recirculation) valve with a solid stainless steel plate (about £5 online) will prevent this happening, the engine will also run better at part- throttle, (in the EGR "activation zone") because engines run better on clean air, than burnt exhaust gasses - as yours is a euro4 Mondeo - its likely your EML (engine management light) may come on when you blank your EGR, a code reader (approx £20 online) can reset this (some do this once a week)
Injector cleaner will not make any difference to this problem, IMO, some injector cleaner/ "snake oil" contains parrafin, or other solvents which can cause problems (eg - melt seals) with continued use. Some modern diesel fuels contain detergents,(Shell/ BP "super-dooper" fuel, whatever they are calling it this year) to help clean out the injectors - this is a safer option
The mk3 (Mondeo diesel) was never designed for the low- sulphor/ 5-7% bio deisel dispensed from the pumps in 2013, the injectors may wear faster than they should, the delphi injectors are already "soft"
The other thing (apart from the EGR valve/ system, already mentioned) that is soft is the DMF (dual mass flywheel) at 130K it may be on its 2nd or 3rdone, if not, 100k is about the limit on these things, - mine "went" about 100k, i "nursed" it for almost a year after that, then i fitted a solid flywheel, carbon fiber/ kevlar clutch, 30% stronger clamping force, heavy-duty re-enforced backplate, and sprung plate, its not to everyones taste - but i like it - the DMF will never fail again
I don't think its the DMF (wrong frequency) but it may be a contributing factor/ or may add to the problem
Ive never used injector cleaner or expensive diesel (apart from once) i use the cheapest fuel i can find - supermarket pump diesel or veg oil - the TDDI can run on this . It runs very smooth and pulls from low revs - no driveline shunt or hesitation etc
The variable vane mech on the turbo can coke up over time - this can sieze, causing the actuator to fail
Live data or a boost gauge could indicate if your problem is boost-related eg - "boost pumping"