The check engine light came on on my 2003 Altima, 2.5L.

It has roughly 81k and you can start the car and every now and then it will die, and has shown a sign of a slight miss.

It also possibly does not downshift properly.

Is this a Intake Air Bypass Valve problem, MAF, or camshaft sensor issue?

Where is the camshaft sensor located at?

Thanks. :)

Did you ever have the code read to see why the check engine light came on? You can have this done for free at most Autozones.