6 is ECT - engine coolant temp sesor. Make sure the sensor's plug is connected to it(the sensor is located ont he head, under the distributer).

The front torque mounts keep your engine from rocking back and forth. If you're missing the driver side one, than that side of the engine is being supported by the upper driver side mount alone. If you run like this your engine will move around quite a bit, which will wear out the other mounts, and their rubber components will eventually tear. I would not drive very long, if at all like that.