intake idle/start up problems
 

I recently installed a cold air intake on my 06 mazda 3. Since the install I have been noticing some problems and was wondering if I can do something to fix them or just let the computer fix its self.
1. when I start the car, unless im revving the engine, the rpms are bouncing slightly and keep going low and sounds like the car is about to die. ( has died a couple times)
2. when i accelerate it seems like the car is accelerating way slower than normal
3. when I'm on the hwy and the car is in fourth and I have to slam on the gas, the car down shifts to 3rd gear or in a few instances all the way down to second.


My check engine light came on the other day and when i got the code checked they told me it was an o2 sensor.


sorry for the lengthy post. thanks in advance