We had a similar problem on our 2 database servers.

The CHECKPOINT command below fixed the problem. Our TempDB database was not being checkpointed frequently enough or at all. Why does this situation exist? I don't know. We don't have this problem with any other database on our servers.

USE TempDB

CHECKPOINT

From SS Books Online regarding the CHECKPOINT command: "Writes all dirty pages for the current database to disk. Dirty pages are data pages that have been entered into the buffer cache and modified, but not yet written to disk. Checkpoints save time during a later recovery by creating a point at which all dirty pages are guaranteed to have been written to disk."