i dont have the same brand of cai but i am experiencing the same p0171 as you . i got it after i cleaned the filter , maf sensor , and the tb. it means you are getting un metered air into your engine somewhere after the maf sensor or ur not getting enough fuel . i have been trying to track down and fix the problem or a few weeks. most likely causes are a vacuum leak (a small hole somewhere or bad connection) , a bad or dirty maf sensor , a bad o2 sensor , faulty pcv valve, improperly installed aftermarket air intake,dirty fuel filter or bad fuel pump. i ending up replacing maf o rings and then later maf sensor itself that didnot fix the problem . make sure you inspect everything you touched carefully, maybe even take cai apart and reassemble. do you notice any performance issues with the car (jerky accel or decel? or rough idle?)