On the way home from work, I noticed my engine was making a bit of kinda like a rattling sound, not very loud, and it came and went (only noticed it while it idles)

When I got home, I had a look, every 5 or so seconds then engine should shudder a little bit. - more than ive noticed before (still making the slight sound)
I havent really noticed much of a difference in performance, but my initial guess is a spark plug lead, or a spark plug.
Now after finally locating where my plugs are, I thought id ask before pulling my air intake off and that to get to them.
Anyone have any ideas on what it could be if you dont think I might be right with my guess?