What causes the engine light to blink on and off on a rx8?

Answer 1

Hundreds of possibilities. The DTC (Diagnostic Trouble Code) system has detected a fault somewhere. If your car is 1996 to present, you can run an OBDII scan, but in all cars a blinking light indicates a more serious problem than a steady on light

Answer 2

Continuing to drive the vehicle with a flashing check engine light can and will cause catastrophic damage to the catalytic converter(s).