So, a couple weeks ago I find a small blue piece of soft plastic on the floor of my RSX under the pedals. It is half of a round piece about the size of a quarter. Searching the OEM parts diagrams led me to part # 46905-SK7-000, "Stopper, Clutch Pedal". I performed an image search on this part number and found it to be a match for the fragment I found.
This part appears to be common to many if not all Hondas with manual transmissions. I had my wife stop by a convenient Honda dealer to buy one for me. She calls me as she is leaving the dealer and tells me that the new part number is 46505-SA5-000 and she bought one. This is the common pedal stopper used for the pedal switches that we all know and love. I tell her to go back to the parts counter and tell them that this is not the correct part. She finally convinces them to look up the part number and they ultimately determine that it is, in fact, a different part that no one there has heard of and they do not have it in stock. I let it slide until I had a reason to place an online parts order.
Well, the Odyssey needed rear brakes so I finally ordered the correct part along with the brake pads.
I finally installed it. This particular "stopper" attaches to a spot on the firewall behind the clutch pedal and provides a soft stop for the back of the pedal arm to contact when it is fully depressed. I notice the difference now when pressing in the clutch after it being metal on metal for a few weeks.
I imagine most people never replace this part when it fails. Look on the firewall where the pedal arm contacts it to see if this blue "stopper" is still there. If it isn't, you will see a small hole where the "stopper" mounts and part number 46905-SK7-000 is what you need.