Very very flat please help

Hello my mums got a 56 reg old shape td4 freelander and its got a terrible flat spot between tickover and about 2300revs, its so easy to stall at junctions and roundabouts and u have to thrash it to get it anywere, a friend said to stop it it needs chipping. is there any ideas out there because its a big annoyance for such a good motor, thanks

Check for air leaks, damaged hoses etc
Would recommend getting a local grease monkey to check out the turbo, wastegate etc

Sounds like a faulty Mass Airflow Meter, try disconnecting the plug on the MAF and see if the fault disappears if it does this points to the MAF being faulty. When you disconnect the plug the engine reverts to the ECU presets.