1998 Grand Marquis the check engine light starts to blink the car loses power for a short time the light stops blinking and then runs fine, It does not apear to be overheating, this may happen off & on all day
A blinking Check Engine light indicates a misfire. You need to have the codes read from the computer to determine the cause of the misfire. Parts stores like Auto Zone will pull codes from the computer for free.
Tester