Car coughing? (Possible Misfire?) & Engine cutting out.

[SaMk2]

My car is currently idling at different revs, and every few seconds it chokes, and the revs will drop, even on occasion the engine will cut out.
Someone on the thread has mentioned a possible idle control valve, but I've noticed now that this has turned my car into quite a bumpy ride.
Im starting to think that this was a spark plug on its way out, that's now dead altogether.

The only thing is, I'd rather learn and do it myself.
As far as I can tell I've figured it can be anything from Lambda, sparkplug, coil pack, leads or a faulty injector.
So I might aswell do one at a time and see what happens.

Though as Im completely lacking knowledge in terms of doing this;

First things (and perhaps easiest) first, are there any guides or can anyone give me a brief introduction to how I'd change my spark plugs/ and or cleaning the throttle body

Thanks for your time guys

 

[TooneySonic]

Lambda, just had mine on diagnostics with exact same symptoms and its what flashed up. Had new plugs and leads within last 12 months