Both the above statments do not sound right.

If and ECU is fooked. Its fooked, as in wont even start. If it was another problem with the ECU it will not effect the ISCV apart from making it tick as it is connected to the same wire that is used for the fuel pump and a few other sensors.

If the Air to Fuel ratio is wrong or out of adjustment etc.. it could lead to hunting as will some sensors being U/S.

Get it to somone who can check it all out with diagnostics equipment.