Hi,

Re the TPS, it should be open circuit when idle, with the output decreasing the further the throttle is opened.

The ECU looks for an open circuit to active it's idle and overrun strategies.

The idle screw sets the base idle only (which will need to be setup, as you have adjusted it now) I suspect if you disconnect the ISCV it will stall now.

To do this the car has to be at running temperature with no electrical load and the ISCV disconnected, the idle should be 850 RPM (IIRC) and when you reconnect the ISCV the engine speed will increase for a moment and immediately drop again.

Both the TPS and the base idle should be corrected first, as you will never get it idling nor running correctly otherwise.

Martin