How do I optionally slow down cucumber (ruby) tests?

I have tried googling, but had no luck. Maybe I just don't know the terms to search for...

Recently we made some changes to the environment, and now tests that use to run without issue kill the service. We are working to find out why that is happening... but in the meantime, is there a way I could pass a CLI command or something to slow down the tests on demand? (or vice versa, run at full speed on demand) Or maybe build something into a rake task?

I know I could easily add an after hook to sleep between scenarios, but I want to be able to run the tests full blast as well while we are trying to sort out the issue. Adding an after hook would require editing several files every time we wanted to turn the throttling on or off.