You may want to do an idle relearn, If you did not already do one.
1) Insert key into ignition and turn to the "On" position but, DO NOT START THE ENGINE.
2) Pop open the fuse box cover and remove the two 10amp fuses from position numbers 16 & 23.
According to the manual there are 2 fuse boxes. Use the engine compartment fuse block for this procedure.
Instrument Panel Fuse Block (wrong one): 16 is Air bag and 22 is Body Control Module - Ignition and 23 is Body Control Module - Ignition 2.
Engine Compartment Fuse Block (correct one): 16 is Powertrain Control Module A and 23 is Powertrain Control Module B.
Note. Your DIC will now display "check" messages for ABS, etc... Do not worry. This is normal.
3) Go back to your cockpit and turn your key to the "Off" position.
4) Return to the fuse box and re-insert both 10amp fuses for positions 16 & 23.
5) Go back to your cockpit and start your engine. Allow engine coolant temperature to reach a minimum of 176 degrees F. Allow engine to run at this minimum temperature for at least 5 minutes.
6) After a minimum of 5 minutes, at 176F, shut down engine and let rest for a minimum of 30 seconds.
7) Restart engine - check for DIC error codes (there should be none).
/phpBB/images/smiles/icon_cool.gif Drive car for a minimum of 30 miles at varying rpm settings and speeds. PCM will now re-learn and adjust for the new air flow and air temperature at the intake.
If error codes persist, repeat steps 1-7. Make sure fuses are properly inserted before repeating steps. Do not void the sequence outlined above. If you do, restart sequence from scratch.
These steps combine everything I have learned from various sources for changes made to the MAF and air intake. Steps 1-4 are also necessary if you ever disconnect your battery or, lose power for any reason.
If you have done this already. You may want to check for air leaks. This can also cuase a surge in the idle. I used the above procedure when I installed my Haltech and the idle remains very smooth.
Hope this helps.