Hi there kez,
Forum search systems are historically useless, but there are some tricks you can do to make them a little more effective.
First, if you know the poster, then input one keyword and the username of the person you know said it. In this case, I used "plug" with the username "JoeUSA".
Secondly, if you're getting too many results to be useful, you can restrict the search by category. If you know the post was made in "Fuel", only search that category.
Lastly, display the results as posts, and not topics. This will allow you to see the actual post that matches your search, and you can view the first X numbers of characters in the post(default is 200). This will allow you to browse your results without having to bring them up in a new tab or window.
No magic bullet, but that will make your life easier when you've got to find something
thanks,
json