Nick - it sounds like you've covered all the possibilities to me. Early on in my ownership, before I realized how the speedo system worked, I had taken of the wheel and was inspecting the dustcap/speedo setup. There was some grime built up on the lip of the dustcap, so I wiped it clean, and also cleaned the rim where the cap seated. Everything was nice and shiny clean when I reassembled things, but when I actually drove the car, I found my speedo no longer worked correctly. It seeemd to work correctly at slower speeds, but as I got faster, it would jump around a lot, and sometimes drop to zero. I had thought that the pressure from tightening the lug nuts would be enough to hold the dustcap in place, but it was appaent that this did not happen. I ended up using a thin bead of lock-tite on the dustcap. That fixed the problem and I haven't seen any other problems from my speedo since. You said you marked yours, and it didn't appear to have moved, so I may be barking up the wrong tree, but your symptoms sound very similar to mine. Good luck, Dave vin 16367 To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: mailto:dmcnews-digest@xxxxxxxxxxxxxxx mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/