P0171 code
 

I have a 2005 Chevy Cobalt SS/SC and today the engine light came on so I took it to autozone to see what code it was throwing and it was the P0171. My car has been making this funny noise like the sound of an exhaust leak when I accelerate. The noise started a few days after I took my car in for an oil change about a month ago at Valvoline. When I got home today I popped my hood to find that my air duct going to my supercharger has been loose for over a month so I tightened it and it still makes the noise like it has an exhaust leak. There is a stage 2 done to my car with the bigger injectors and smaller pulley, however, everything else is factory except the clutch which I wouldn't think would cause a problem. Could this loose air duct have messed something up?

Check your air duct again, maybe it has a hole in it, Also check the hose that goes between your air duct and the back of the engine for holse. Check your vacume lines for holes leaks.

P0171 = System Too Lean,
If your not modded, it means that your getting more air in your intake, the what the MAF (Air flow sensor) is sensing, so its makeing you run lean (Not enough fuel for proper combustion)
I say keep checking your lines/hoses and espessly your intake ducting for leaks. Take out a section if you have to (if you have the stock intake) Check where the intake goes down behind the headlight for leaks, and check where the intake goes in front of your PCM for leaks. Look arround while the engine is idleing see if you can find / hear the leak that way.

flex pipe? hold your hand under it while its running maybe it has a crack in it. would that cause it to lean out?

That would probably throw an O2 sensor code.

Hey bro I am in vine grove, if you want you can come meet me and I can look at it for you.......

I went to autozone again today and bought some Lucas fuel cleaner and some throttle body cleaner. I put the Lucas in and went to spray the air duct out when I noticed the rubber on the air duct where it meets the supercharger was all kinked up. I went to put it all on where it makes a good seal, drove it around for a little while and the check engine light went off, however, it still makes this noise like it has an exhaust leak and it only does it when I'm in gear and not in neutral.

Bro I live close to you if you want to ride down......

I might have to ride down there next weekend if that would be okay, could you inbox me your number?

Lol everyone has my cell number lol 270-505-3212..

Sub

A replacement Ho2 Sensor fixed this issue when I had the System too lean error.

What did the problem end up being? Im having this issue to

At work we had a 2007 SC and it was 100% stock and kept throwing P0171. Ended up being that air was getting in after the MAF in the intake. Just wasn't sealing 100%. Dealer took forever to figure it out though, but they ended up sealing up all the joints in the stock intake and I think they replaced one or two vac lines for the boost bypass valve.

Maybe this will help.

I will check my intake when I get home... Hope its just that the intake pipes are loose....