So they told me to put the stock air box back on and that the problem is that the MAF sensor got a film of oil on it and can’t read air intake correctly. Also said that the engine was not engineered to get all that extra air. They told me they would clean the sensor and do a re-learn for me. But I had to talk to the service manager to get this “treatment”. The service advisor just told me basically “oh well , you installed an aftermarket cold air intake and that is the problem, we have this problem about 1 time a month. and we can’t do a re-learn to your transmission since there are no updates”......in your case with the 2018 8 speed transmission there is apparently an actual update from GM to help with the hardshifting 2015 Silverado LT Midnight Edition 4.5” CST suspension lift Sent from my iPhone using Tapatalk