Intermittent Starting Problems Cranks but wont Start

This problem will happen when it wants to, I have removed the connector that houses the ignition switch module and cleaned but this has not helped. I have read that it might need to be soldered directly. The Immobiliser light on the left upper corner is on when this happens and will not go out. The key will open and lock all doors. I just need to be pointed in the right direction to fix this.