I have a 2006 2.4L Cobalt SS and the check engine light keeps coming on randomly. I might make my near 20mi drive to work without it ever lighting up, some days it'll be on the whole day, or it might come on then shut off several times during any drive. I've tried 3 times to get the code checked, but as luck would have it; it's gone off each time before to plug is even in.
I've tried changing to high octane and injector cleaners, checked all fluids (still about 1000mi till the next oil change too), throttle body cleaner, cleaned the air filter, etc... Nothing has made any difference in the "light behavior" and that aside there is no change in the way it run or drives.
My only guess left is maybe something off with the O2 sensor, that aside, I'll need the light soon to pass the emissions test -_- Any of you had a similar issue and did you find out what caused it?

 

The code isn't stored?

Without it the code it could be thousands of things that can set it off. Some minor some major.

 

if u dont have a code reader just go to a autozone or a o reilly and have them read the codes for u

 

The code will be stored get it checked

 

That's what I've tried since I don't have a reader. The first 2 locations I was at said the code isn't stored and I just kept driving on the 3rd attempt with that presumption since the light cut off when I got in the parking lot.

It did seem odd that something like that wouldn't be stored, but thought it odder that 2 people at different store would make the same mistake.

 

UPDATE!

Stopped by Autozone and had the light on this time, I got code P1174 (Air/fuel imbalance). The possibilities they gave for getting the code were, bad gas, needs tune-up (99,600 miles on it, so I was doing that in the next week or two anyway), needs new fuel filter, needs intake/injectors cleaned, and as suspected, needs a new O2 sensor.