if your t2 is mechanically throttled, (a cable) then you can follow the cable back to the pump and find the cam shaped well, cam. what it stops against is a screw, this will need to be tightened to increase the revs at idle. it will be awkward to adjust but that is the idle control it will be worth checking the throttle pot on the pump too as it may feed ecu with accel position aswell as egr valve. if it electronic, then there will be a throttle position sensor either at the throttle pedal or somwhere with which to reference accelerator position. it will be slightly off if the revs are low either as it has moved slightly, or the contacts are not clean inside the unit. i can't really tell as i am not familiar with electronic controlled throttle on these, but it should be fairly obvious if there is something with wires connected to the accelerator pedal.
richard