Very High MySQL Calls to tmp Directory


I am having an issue with my current installation of WordPress MU (3.1) causing an EXTREMELY high query calls to the tmp place within the database. It is so high that is consistently crashing my host.

I am having trouble pinpointing the issue. I've tried shutting down many of the plugins, then doing a check and its still occurring.

I am wondering if someone has seen this before or they could suggest certain lines of code, files, etc to check for this.

Thanks for any help in advance!