Hi folks,

I have an 03 explorer, V8 Eddie Bauer. It's had a rough idle for a little while and the other day my check engine light flashed at me. Looked up the codes and it told me I had a couple cylinders misfire and a couple codes saying "system too lean" bank 1 and 2.
I'm certainly no professional but i always like to give it a go when I think I can manage.

So yesterday I took out the MAF sensor and cleaned it, changed the air filter, and changed out my spark plugs to start. (Spark plugs were due to be replaced)
I started her up again and she sounded much better. Went for a quick spin and it seemed like the troubles were gone. Sat inside in the driveway for a few minutes and the idle got progressively worse. Opened the hood and had a look and after a few minutes it just died.
Started it up again and it died a few minutes later.
It starts up fine and drives fine but the idle is rough and dies out after a bit.
So this morning it wouldn't even start. Battery is fine, it still turns everything on, but I turn the key and it just makes one click noise and doesn't do anything.
Any ideas??
Much appreciated!