I recently bought a 2005 Chevy Cobalt LS sedan. It came with around 54000 miles but it was sitting on the lot since November but my steady check engine light keeps coming on. Is there any reasons to why? I checked the hand book for answers and those aren't anything that is wrong with it. I also had Auto Zone look at it and they tried 3 times to see the problem but nothing came up. I just unhooked the battery to see if it'll stay off but if anyone has any answers please let me know. Thanks again

PS: Chevy RULES!

 

Try checking the fuel cap or possibly replacing the fuel cap. Any slight problem with it that allows air to enter can cause the light to come on and stay on.

 

I did check my fuel cap and it seemed fine but idk. I undid the battery earlier to reset the car and it came back on. Its not as though it drives different at all. Came back on tonight while i was on cruise control.

 

Have it scanned while the light is on, there should be a code to be read while the light is on