1. Disconnect the Negative battery lead.

2. Install the CAI (Cold Air Intake), as per the manufacturer's instructions.

3. Verify that the Negative Battery lead has been disconnected for a minimum of 30 mins. (I normally give it an hour)

4. Reconnect the Negative Battery lead.

5. Start engine and let idle for a minimum of 15 minutes. (On my Suburban I ran 15 minutes with AC on then switched the AC off and let it go another 15 minutes. Then ripped it up and down the street a couple time at Wide Open Throttle.)

What does this do? All newer vehicles are equipped with ECU's  (Electronic Control Unit) that "Learn". Disconnecting the negative battery lead clears the "Learned" programming and returns all ECU settings back to stock. (Depending on the vehicle, this may or may not clear codes). If you have a CEL (Check Engine Light), be sure to clear the code before you begin. The 15 minute idle period in step 5 allows the ECU to re-learn and compensate for the less restrictive CAI, (Cold Air Intake). Learning time varies from vehicle to vehicle.  Also, some vehicles are just angry, if you follow the steps above and find that you have a rough idle after the learning period with the AC on, I would suggest following steps 1, 3, & 4 again, then for Step 5 let the vehicle idle with the AC on. This will allow the ECU to "Learn" with the additional load on the engine that the AC causes.

Additional note: Some cheaper Cold Air Intake's have incorrect pipe diameter, and or MAF (Mass Air Flow Sensor) housing that causes the Mass Air Flow Sensor to read the intake air flow incorrectly. I  have had Cold Air Intake's in the past that no matter what I did caused lean codes to be thrown. After checking the plugs, the lean condition did not seem to be causing issues to the engine except running out of spec just long enough for the O2 sensor to cause the ECU (Electronic Control Unit) to pop the lean code. If you are still getting lean codes, be sure to check your plugs for signs of lean condition and get rid of the Cold Air Intake if you do see that your plugs are showing lean.

Hope this helps.