Quick answer: Gas cap or 02 sensor
Or, it could be anything. When mine came on (04 Liberty Sport) I bought a scan tool at Sears. Turns out it was an O2 sensor.
My 02 liberty check engine light has blinked in the past. It was because my battery needed to be replaced. Count the number of times it blinks and search for that blink pattern online for better information.
None, it might cause oil to spill on your engine or inside of your hood, or a dash light might come on.
There are pages and pages of things that can turn the check engine light on. You need to have it checked for codes to know what the cause might be.
It might cause the "check engine" light to come on.
It might be that you did not tighten the gas cap enough.
Have vehicle scanned to determine problem
If the fuel pressure is too low that might cause the service engine light to come on and , since there would not be enough fuel pressure, might also cause a sluggish response. That could be caused by a clogged fuel filter also.
Your bad muffler might be part of the reason your check engine light comes on. Usually, your bad muffler causes something else to go wrong and that causes your check engine light to come on. Problems cascade.
Is it a fish smell or a rotten egg smell ? FISH SMELL COULD BE A BAD HEATER CORE, THIS WOULD CAUSE YOU NOT TO HAVE HEAT IN THE CAR , BUT IT MIGHT NOT CAUSE CHECK ENGINE LIGHT TO COME ON UNLESS MAYBE CAR IS LOW ON COOLANT. ( THERE MIGHT BE A LOW COOLANT SENSOR TO TRIGGER CHECK ENGINE LIGHT) ROTTEN EGG SMELL COULD BE A CLOGGED CATALYTIC CONVERTER , WHICH WOULD CAUSE THE OXYGEN SENSOR TO TRIGGER THE CHECK ENGINE LIGHT, BUT IT WOULDN'T CAUSE THE LOSS OF HEAT.
my car had that problem when i washed the engine with water, check the sparking plugs, they might be wet, keep it dry and it will be ok .
There are pages and pages of things that can cause a check engine light. You need to have it checked with a scantool. Then the code can be diagnosed and repaired.
Several things could cause the 2001 Impalas check engine light to stay on. Since so many things could be wrong, check the computer codes for any leads on possible problems.