Debug irrelevant Wordpress search results

On Wordpress, I keep getting irrelevant search results.

• Some search strings that do not exist on the DB yield All Posts as results.
• Some search strings that DO exist, works great.

What could be the cause of that behavior? I've uninstalled all related开发者_开发百科 plugins. Is there a way to debug the search?

Thanks!

Thanks for the tip, Greg :)

For some reason I thought in the search template would be a good idea. Removed this line, everything is right.