Check engine light on after upgrades

The check engine light is on now after I had a K&N air filter sytem and catback exhaust installed.  On star diagnostics says the engine is running too lean and is sputtering.  Is there anything that I need to have done now to correct his or should I replace everything I had taken off?  Thanks

Keep driving, it may take 100 - 200 miles for your PCM to learn to learn to compensate by increasing fuel mixture etc...
 
 
Make sure the MAF Sensor is properly connected and snapped tight at the plug.

Also with the K&N filters, some are over charged.  (too much oil on the filter).  This can cause issues as well.