So, I'm working on my girlfriends 2006 Chevy Cobalt 2.2L.

We live up in Alaska and when it gets cold, its always had trouble with the battery being the in the back. Thanksgiving night, she didn't plug in her battery blanket to keep it warm and by Friday morning it was dead, even though it was a relatively new battery. I tried jumping it and it didn't work. So I was talking with some friends and trying to figure out some solutions, and our landlord, who is also her boss, was trying to help and towed it to a shop.

The shop let it sit inside all night, and tested the battery. After a bad test, they replaced the battery and gave us an oil change and was charging us close to $200. They were able to start it, but it sounds awful, almost high pitched and really rough, and it runs extremely bad and the moment you take your foot off the gas it stalls and dies. After the $200 which her boss paid, the mechanics literally told us that it sounds like **** and that they'd could take a look under the hood but it'll cost us. I'd rather do it myself.

Here is what I've done to it, after getting it started the check engine light went on and so I go that read, with over 6 codes. I changed the MAF sensor, and now the codes are dropped to P0326 and P0300 which are knock sensor 1 and multiple misfires. Just as a precaution I've also replaced the fuel filter. Now, I'm heading out to clean the throttle body.

My question to you guys, what else could it be: a terrible sound while running with the gas pedal depressed, the moment you let off the gas it stalls and dies. (My next two ideas would be spark plugs and then the fuel pump, but I'm hoping its not that.)

(If you haven't already deduced this, I started working on my car about a year ago to save money from the shops, so I'm fairly new to all this, but I've been a quick learner.)

 

Sounds like some sort of mechanical failure in the engine from what you describe. How many miles?

Any ticking noises or anything weird before it wouldn't start? Makes me think like something broke in the valvetrain and is making terrible noise and limiting airflow.

 

Given the battery is crapping out, I would check you're serpentine belt and tensioner as it could be the cause of the high pitch squeal. Is it an auto or a manual?

Also the knock sensor being bad and bad plugs could cause issues.

 

Plenty of other good suggestions here to check on, but this is the exact same thing both my Olds and my roomie's Cavalier did when the cables from the batteries were corroded, so that may be worth checking.

 

Didnt think of that being a 06 and I'm assuming there is a chance of corrosion

 

My car did the same thing. Bad cable and battery. It happens. I would suggest a deep cycle battery. Odyssey, optima etc.

 

How cold is it?

 

Yeah an AGM battery like an optima might be better for you.