Uneven brake pad wearying?

Check the caliper sliders that are behind the rubber protectors located on the caliper bracket, Chances are they need to be cleaned and greased up There's also a chance it's time for new rotors. The Honda rotors these day's make it through 2 pad replacements before it's time for new ones. The material now a day's pads are made of is harder on the rotors where as the rotors are no longer able to dissipate the heat, tend to wear unevenly, and fall under the rotors minimum thickness specifications. The Idle being lower than normal I doubt if changing spark plugs will help. That is if the low idle isn't caused from a miss fire, Look for hard spots or signs of arcing in the wires, however using an ohm meter is the best way to check them. When you Twist and Pull your spark plug boots off check the ends of the wires for signs of oil which would indicate leaking oil tube seals which Honda's are notorious for. Good Luck and Hope this helps.