P0446 - EVAP emission system vent control circuit
P0301 - cylinder 1 misfire detected
P0300 - random/multiple cylinder misfire detected
P0303 - cylinder 3 misfire detected
P0304 - cylinder 4 misfire detected
P0302 - cylinder 2 misfire detected
P0451 - EVAP emission sytem pressure sensor / switch range / performance
P0496 - EVAP emission system high purge flow

This **** SUCKS!!!!!

 

Did you over rev it? That'll cause misfires galore. Check your plugs, I found .032 gap works well.

 

Change plugs.

 

Car is at dealership as we speak, but they wont get to it til Monday. And no I dont over rev, I mean I have used LC a couple times, but that is it.

 

My car throws the P0300 all the time. Mostly an immature code. I don't even worry about it. I just clear it and go on my way.

 

I'm not all that great when it comes to technical ****, but with it saying I was misfiring on all 4 cylinders, that cant be good. You think my performance was lacking because of this stuff?

What are the stock spark plugs gapped to in these cars? I'm FutureEcotecOwner's brother and I'm just wondering. What plugs do you guys recommend for his Cobalt? I use NGK 4306's in my skittle gapped to .030 or .032.

 

Most swear by the stock plugs. I run NGK Iridium's 2 ranges colder with no issues, but mine are all highway miles. No misfires detected gapped at .032

https://www.cobaltss.net/forums/2-0l-lnf-performance-tech-153/update-ngk-iridium-ltr7ix-11-plugs-after-1000-miles-188462/

That thread shows them at 1000 miles, I have ~3,000 miles on them now.

LTR7IX-11 (6510) are about 2 ranges colder AFAIK,

LTR6IX-11 (6509) are ~1 range colder.

I went colder after increasing boost and to try and reduce some knock retard of the timing.

 

What kind of plugs come stock and what are they gapped too?

 

bump for update

 

I think you have a bad purge solenoid. It is located on the top driver's side of the engine. It is most likely the cause of all your codes.

 

did u get on it when engine was not at running temp?

check ur gas cap. if its not on right it will throw a evap code.

did u get on it when engine was not at running temp?

check ur gas cap. if its not on right it will throw a evap code.

 

Sorry for no update, didnt think anywhere cared what was wrong, LOL. The Dealer fixed it under Warranty and said it was a bad purge valve. Have had the car back for about a week now with 0 problems.