A friend’s 1992 Honda Accord (4 cylinder) started idling at full throttle, 7000 RPM. I didn’t find any reference to this problem on the Internet so I thought I’d share what I found.
I started looking for broken vacuum hoses, a stuck accelerator cable, or anything easily visible, but found nothing out of the ordinary. So I took the top off the fast idle valve and it was full of pink shredded paper. I unscrewed the white plastic ring from the valve, lifted it and the valve out, and cleaned the paper out of it. Then I removed the large (4 or 5 inch diameter) air hose that's between the air filter and the engine. It was also full of shredded paper. I cleaned it, and got the paper out of the throttle valve and surrounding areas. Then I took the top off the air filter and it was half chewed up. I took the filter out and found a mouse nest under the filter with 3 newborn mice (not alive). I cleaned all that up, put in a new air filter, and it ran normally.