Correct Lamda Sensor for a 2005 VVT M13A Jimny

Some progress. I've cleared all DTCs with the scanning tool, then checked and cleaned the PCV valve as suggested. I have not yet cleaned the IAC valve as the weather was not great. The Suzuki repair manual lists all steps how to remove the IAC valve. Starts with: Disconnect negative battery terminal. Drain engine coolant. Release pressure from fuel system. Disconnect hoses and sensors. Remove throttle body (incuding the IAC valve) then separate IAC valve...on top of this the rubber O-ring is not reusable. That's great. So I've ordered a new IAC valve with new seal.
As a desperate attempt to find out what's wrong I was playing with the accelerator pedal to see how the engine reacts. After 15-20 minutes of running I noticed that the idle RPM randomly went low then surged. Turned out just run out of fuel.. Added 5l of fresh 99 octane petrol then fired up no problem. I reved the engine again a few times and each time the idle RPM dropped a bit. Eventually the engine has settled on 950 RPM! It's still higher then normal but much better than before.
Could this be the a sign of dirty IAC valve?
Is it possible to simply remove the IAC valve (undo 4 bolts, disconnect wire connector and disconnect 2 hoses) without draining coolant and removing throttle body? 

Progress.

I haven't taken the IAC off mine, so can't advise if you need to drain the coolant, perhaps a Google search to see if anyone does it without?

However, the coolant is easy to drain, there is a plastic drain on the bottom of the radiator and since the IAC will be near the top, I doubt you will need to drain very much out.

I took my radiator out [twice] when changing the crank drive belt pulley, it's a quick job.

Robin

Well, it's been 7 months since I was here. During these month I was not able to investigate the cause of idling problems of my M13A engine. All I could do recently is removing and cleaning the throttle body and the IAC valve as suggested.
Despite of a thorough clean there is no improvement. I run out of ideas. Looks like it's not going to be running for the rest of the year. Photos before cleaning.

Thanks again DrRobin for sending that link in November last year. It will be my guide.
suzukijimny.automotive-manuals.com/S8R70A1124010.html 
Here is the list of things I need to check:
 
Seems endless, but I'm not in a rush.

The inlet side of the throttle body look reasonably clean, but the engine side has a lot of deposits on it, unless this is the before picture?

You might find these deposits are causing the butterfly valve to stick. That would explain the uneven idle but not the fault codes.

Robin