The computer has detected a problem and there is a code available for you to read. That is the purpose of the light.
Have the codes read.
It means your engine needs attention.
Have vehicle scanned to determine the problem
Thousands of things. Take it to a mechanic who has a scanner and they can tell you what the problem is.
does the light illuminate during start up? If not the lamp is burned out. If it does, then the engine computer is likely at fault.
Have vehicle scanned to determine the problem
I have a 1998 ford grand Marquis- and the problem is the air suspension light stays on- how to fix this problem
That is one of hundreds of possibilities. See related questions below.
How. Do reset airbag light on a 1993 grand marquis
The check engine light indicates that the computer has detected a "fault". Use a code scanner to find out what the computer has detected, that is PROBABLY the reason the engine is running poorly.
You can but the check engine light will remain on and it won't pass an emissions test.
If Its an older Grand Marquis its easy. Find the knob that you pull out to turn on the headlights. Now, just turn it clockwise and the light will turn off!