Yes, a lot of tools, including some like w3af do: https://github.com/andresriancho/w3af/blob/fb345a5/w3af/core/controllers/delay_detection/exact_delay_controll

Yes, a lot of tools, including some like w3af do: https://github.com/andresriancho/w3af/blob/fb345a5/w3af/core/controllers/delay_detection/exact_delay_controller.py#L114 https://github.com/andresriancho/w3af/blob/fb345a5/w3af/core... This one sends the payload reversed as a test to see if the delay is due to the SQLi attempt