Light Turns On Solid; Light Is Blinking - Mercury Sable 2001 Owner's Manual

Instrumentation
The indicator light illuminates when the ignition is first turned to
the ON position to check the bulb. If it comes on after the engine is
started, one of the engine's emission control systems may be
malfunctioning. The light may illuminate without a driveability concern
being noted. The vehicle will usually be drivable and will not require
towing.
What you should do if the

Light turns on solid:

This means that the OBD II system has detected a malfunction.
Temporary malfunctions may cause your
Examples are:
1. The vehicle has run out of fuel. (The engine may misfire or run
poorly.)
2. Poor fuel quality or water in the fuel.
3. The fuel cap may not have been properly installed and securely
tightened.
These temporary malfunctions can be corrected by filling the fuel tank
with high quality fuel of the recommended octane and/or properly
installing and securely tightening the gas cap. After three driving cycles
without these or any other temporary malfunctions present, the
light should turn off. (A driving cycle consists of a cold engine startup
followed by mixed city/highway driving.) No additional vehicle service is
required.
If the light remains on, have your vehicle serviced at the first
available opportunity.

Light is blinking:

Engine misfire is occurring which could damage your catalytic converter.
You should drive in a moderate fashion (avoid heavy acceleration and
deceleration) and have your vehicle serviced at the first available
opportunity.
Under engine misfire conditions, excessive exhaust temperatures
could damage the catalytic converter, the fuel system, interior
floor coverings or other vehicle components, possibly causing a fire.
10
light illuminates
light to illuminate.