i purchased a 2006 colbalt ss/sc. that has a K&N and after market exhaust. i'm now having issues and i'm lost. in feb i tried to get my car inspected and it wouldn't pass. i've been getting a code P0171. i've taken my car to a neighbor garage and spent 500.00 and it still wouldn't pass. i'm wondering if i need to purchase a stock airbox and replace the K&N and see if that works. if not my only other option i believe is the catalytic converter. i did received a letter saying there were problems with the cat but if i wasn't experiencing those issues they listed not to take the car to a dealer to have the cat replaced.

any ideas? i don't kow much about this car and i feel like i'm getting the short end of the stick.

now that my car wouldn't pass inspection i got a letter from the state saying i can't register my car until it does.

 

Short of moving, I'd suggest look for any air leaks downstream of the maf sensor. That code has something to do with lean fuel mixture which surprises me that that would not pass an emission test. But if that would cause it to not passs, then it definatley does exsist. Also for any vacuum hoses loose/off.

 

Welcome to the forum. It sounds like you have one of those junk CAIs. The ECM determines the air mass entering the engine from the MAF sensor input and known dimensions of the air passage. A CAI will often throw the calculation off by messing with the diameter or the shape of that air passage. Install the stock air cleaner outlet duct as you mentioned or find a way to reduce the diameter of the duct work right at the point of the MAF sensor and you should be good to go.

 

like i said i'm not a car person, but i'm learning. i guess you have to start somewhere. can you tell me what CAI, ECM and MAF stands for?

 

by the way...thank you for the welcome...i'm hoping to learn a lot from here.

 

CAI is cold air intake
ECM electronic control module (computer)
MAF mass airflow sensor, thats the thing behind the air filter that measures the flow (pitot tube, basically) and sends a hertz signal to the ECM for fuel scheduling. As posted, and I missed it, the MAF has to be sized (like an orfice in a pipe) to the deminsions of the duct. If you have enlarged the air intake duct without a "compensated" maf to fit it, this will cause an error to the ecm.

 

thank you. i doubled checked on the notice about the cat and it's just a bulletin so for now i will leave the cat alone. hopefully replace the intake will solve the problem. if not i don't know what i will do.

 

I assume you mean the air inlect duct that the MAF is in. After you do, can you clear the code? If the problem is not resolved, it will come back quickley. There also is an RTD? or a temperature sensor behind the MAF that might be causing issue. To measure flow you also need temp. Although I've not had one go bad, that also equates to the ecm.

 

There is no other MAF you can buy or anything, with these cars they need to be calibrated. If you are running an intake and/or exhaust and are not tuned for it, the fuel trims are all over the place. If you are interested in a tune, please contact me through my site- www.badnewsracing.net and I can help you out. Not only will you pass emissions, you will pick up power. Changing the velocity or direction of the airflow over the MAF will make it run rich or lean, but it will be fine once corrected. If you want to stay local, you should be able to find an LSJ tuner near you that can help. Or take it to a tuning shop that specializes in HP Tuners.