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Discussion Starter #1
I cold started my car and it stuttered in reverse and rpms dropped but
then it smoothed out and not sure if that was caused by the oil pressure
being low or the evap purge code. I'm not sure what code it was but I went
to autozone to get it read and the guy told me to tighten my gas cap. I did and
reset the codes and then It came back. But usually its after it sits for a while and
I start it the code will come back. I accidently put higher octane gas in it but not sure if
that has any thing to do with it. Also the purge valve is a little loud but I thought it was normal.
Why am I getting these codes?
 

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What kind of mileage?
Do you ever use ethanol?
Did you change the purge valve?
Bad purge valve can make your car harder to start and may sputter when it does.
 

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Discussion Starter #3
95XXX miles
never use ethanol
Did not change purge yet because I was told it was gas cap.....
never really had a hard time starting it ever....
It starts fine but wants to bogged down after
releasing the clutch after cold starting it and driving it immediatly
that is the only time the code has come on, once my engine
is warm and I shut it off it wont do it again
 

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At what mileage did you change the spark plugs?
 

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Easiest way to test the purge valve is take it off and put it to your mouth and try to blow air through it, if you can its cooked if you can't use a 9v battery with gator clips once you get power to it give it a good blow with your mouth air will go through. If you don't hear a click then it's not opening again cooked. But if it clicks just tap it some times charcoal from the canister finds it way there light taps on a hard surface will clear it out then give it a couple blows with valve blow in the direction that the vapor enters intake. Like what my boss always says nothing a blow job can't fix lmao
 

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Did you check your charcoal tank? Its used in the EVAP system and feeds the fumes from your gas tank to your intake manifold. Ever overfill your gas tank on a hot sunny day? That can be a huge cause of the purge valve. The purge valve is located between the charcoal tank (above the fuel tank) and the intake manifold and its considered an EPA regulation, also to enhance your MPG/emissions.

Other sources:
-E85
-Ethanol
-Methanol
-Fuel Additives (such as octane boosters)
 

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Did you check your charcoal tank? Its used in the EVAP system and feeds the fumes from your gas tank to your intake manifold. Ever overfill your gas tank on a hot sunny day? That can be a huge cause of the purge valve. The purge valve is located between the charcoal tank (above the fuel tank) and the intake manifold and its considered an EPA regulation, also to enhance your MPG/emissions.

Other sources:
-E85
-Ethanol
-Methanol
-Fuel Additives (such as octane boosters)
Stealth I know your trying to help but honestly bro alot of the posts this poor guy is getting is just rehashed from other users.

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DTCart. Another thing you can do is take your air compressor if you got one. and blow air through the vent pipe (the one that goes up towards the fuel cap) I did that to mine and it fixed it. come times crap like dirt or road salt can find its way in there. Give that a go and report back to me. Also if you changed your plugs make sure you got it gapped at .32 some guys say .40 but .32 is what its suppose to be. If the purge valve is louder then normal I dunno how you can hear it i cant hear mine lol. just replace it they are only 30 bucks anyway.
 

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Also if you changed your plugs make sure you got it gapped at .32 some guys say .40 but .32 is what its suppose to be.
Where did you get that info? 2007 Owners manual says:
Engine Specifications
Spark Plug Gap 2.2L L4 Automatic,Manual 0.040 inches (1.01 mm)

Spark Plug Gap 2.0L L4 (Supercharged) Manual 0.039 inches (1.00 mm)

Spark Plug Gap 2.4L L4 Manual, Automatic 0.040 inches (1.01 mm)
 

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I got .32 never a problem coby. The only error I had was the 446 code I posted on awhile a go and your daughter had the same problem I just cleaned my evap system with 20 psi of compressed air and code went away
 

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I got .32 never a problem coby.
I'm not saying .32 is going to give you a problem but it's not the recommended gap. A wider gap makes a hotter spark. .40 is the recommended gap for his car.
 

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Discussion Starter #12
Ok I'm going to described this a a little more and
answers a few questions. Ok first the new plugs
were pre gapped for my car.I also did over fill my
gas tank a week before this happen.. but it was
because the pump didn't shut it self off if that helps.
Then I tried a higher octane gas for a week and have
been off it for two.I have used injector cleaner and it doesn't seem to help.
I have reset the light every time it goes off by unhooking the battery.
The only time it every gives a check engine light is if I let the car sit for 7-8 hours let it cool then go out in the morning to start it.
It also tends to do it on cooler mornings and I live in Michigan and we had snow this past week haha. Also I have notice that since this has started happening
that my air vents make an almost peeling velcro sound when the car first starts and then they "pop" open.....

any clues?
 

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Your air vents are a completely different system it wouldnt give evap codes for that. Also which evap code are you getting p0449 p0446 p0452? Also did you try the fix I suggested because it worked on my car. Not to flame coby but I posted about my 446 code and he said his daughter had the same problem but he never posted a fix for me so I just gently cleaned my lines and shook the canister to remove any loose charcoal and did the same to my purge valve and my code went away. Try it out but use like 18psi when cleaning lines no more or u risk damaging the lines just light puffs will dislodge any charcoal and the vent pipe the air will remove any crud that found its way in there over the years.
 

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Cobalt hasn't stopped long enough for me to fix it, maybe this weekend if the code comes back after it was reset last weekend.
 

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Discussion Starter #15
Ok so I finally got the chance to use a buddies code reader and got p0496. The I checked the purge canister mounted on the motor and I can easily blow through one side but not the other.. is this whats at fault?

---------- Post added at 09:38 PM ---------- Previous post was at 09:35 PM ----------

I found this thread and it sounds alot like my problem.
http://www.yourcobalt.com/forums/problems-service/25706-cel-code-p0496.html

This is the part I'm thinking it may be...but it still clicks as if it was working but like I said I could blow through one end but not the other.
2005-2010 Chevrolet Cobalt Vapor Canister Purge Solenoid - Engine Electrical - Standard Motor Products 05-10 Cobalt Vapor Canister Purge Solenoid - 18305-07124093 - PartsGeek
 

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P0496 is almost always a bad purge solenoid. The plunger gets stuck from corrosion. You can clean it and make it work but it won't last long, better to get a new one.
 

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Discussion Starter #17
Just reporting back to let you guys know it was the solenoid. I got a new one and it works fine no codes this far.
 
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