was driving to hood river this weekend. (From Portland, about 80 miles each way) around the time I got there, I noticed this extra ticking at idle. It kept getting louder each time I came to an idle until it maxed out as a loud knocking during the trip back. Sometimes I can get it to quiet down. The car still seems to run well with power, although maybe a bit hotter than usual when I sit in traffic (not over the white line on the left). One unrelated problem that may help to mention: after highway runs the idle tends to stay high for a while. When this would happen (high idle under no load, usually stopped), I have noticed a little bit of this scuzzy kind of ticking always, which I though was valve noise due to the unloaded high idle, but that now seems to have progressed into this worse knocking, it sounds related. I took a stethoscope to it in several places: valve cover, side of the engine block down low, water pump, timing cover, and oil pan. It definitely seemed loudest at the timing cover. It tends to quiet down when the rpms are higher, especially under load. It almost goes away while driving at higher speeds, although that may be hard to verify due to wind noise. It seems harder to start now too. Oil is not showing metallic on the dipstick. I am hoping this video will help someone to identify the problem.
http://s230.photobucket.com/albums/ee99/zombie-stomp/?action=view¤t=100_3004-1.mp4