Jeep
I assume you are talking about a twin spool engine and mean TGT, Ng and Tq. Not Nf - the power turbine speed.
If it is a FADEC controlled engine TGT and Ng will (should) stay constant once the respective limit has been reached and the fuel flow will become constant (i.e. power limited). In the case of a true tq limiter, the tq will stay constant and the fuel flow will gradually reduce as the rotor droops away from the set datum.
Some engines (OK- I know of one) will have a knee point in their tq-droop schedule (about 15-20% below rotor datum) where the tq limit reverts to constant power i.e. the tq starts to rise again with further rotor droop. This is supposedly to maintain sufficient power to recover (accelerate) the rotor (at a very high blade pitch angle) back to datum from such a low position although it would appear to be a bit academic at that low level as the NR at that point is typical of the minimum NR seen following a successful vertical reject from the limiting Cat A hover height. But then again if you really, really need to keep on flying then sod the Tx limits....
lhb