run on empty

An allusion to a vehicle operating with the fuel gauge pointing to empty or near empty, likely to stop running in the very near future.

run on empty (third-person singular simple present runs on empty, present participle running on empty, simple past ran on empty, past participle run on empty)

1. (idiomatic) To be losing enthusiasm or willingness; to lack motivation.

   He has been running on empty for a while. It's likely the project will be canceled.

• run on fumes