Ah yes, but it wasn’t lean.
There was just lots of unburned oxygen.
I got tricked by that once.
Motor started hiccuping and showed really high numbers on the AFR gauge so I thought it was the fuel pump dying.
Turns out it was a failing ignition module and not a lack of fuel.
Unburned 02 was actually the cause of the lean numbers, and not a lack of fuel.