This site is still very new but we need a bit of help with tagging. I'm seeing a lot of this sort of thing:
Unnecessarily Detailed, Dependent Tags
Tags should help you place the question into a series of broad categories. Tags are NOT there to fully describe the question.
Tag for Major Categorization — The best way to tag a question is to pick out the main subjects covered in the question. Then decide which ones are essential to help people get within the general ballpark of your question. You can get too detailed with tags. Once you have tagged your question with the the major categories, remove the too-detailed tags. The details can be covered in the body of the text.
Tags should be about actual subjects. Is the question above really about "replace" or "resurface"? They're unnecessary. Tags like "fault-finding" are about actions within the question itself and are probably better contained within the body of the text.
Avoid Dependent Tags — Each tag should be able to stand on its own to tell you what the question is about. If you need another tag to understand what is going on, delete the dependent tag. Tags like "2007" or "trouble-shooting" or "manual" or "seized" don't add any categorization to the question. Nobody is searching for questions about "squeaky" or "hidden". Get rid of them.
Avoid Meta Tags — Meta tags do not tell you what the question is about. They describe why the question is being asked (trouble-shooting, help, problem) or what kind of question is being asked (poll, best). Remove these meta tags.
Remove Redundant Tags — Redundant tags are those that are already implied by the site topic of the site. There's simply no value to tags like [repair], [help], [engine], etc. Even tags like [car] and [truck] are going to have limited value. Efforts to coarsely sub-divide the site like that will fail. Tags are not meant (nor well-suited) for the task of dividing the entire site into large swaths for the purpose of participating in (or ignoring) a broad subject site-wide.
Tagging is inherently ad hoc, so I cannot provide a complete guide to come up with the perfect tags for any question. But you can use these guidelines to help other properly edit tags to the standards of this site.