bloke1

Bulletin #06-06-05-001f INFORMATION ON CHANGES IN EXHAUST TONE FOR (AFM) ACTIVE FULE MANAGEMENT SYSTEM I have confirmed problem with GM Senior field reps who state the "buffering noise / vibration when coasting or when the (AFM) kick in to 3 or 4 cylinders. I was told this is NORMAL condition for all (AFM) fullsize trucks and no repairs should be attempted. WOW sounds like all of us have the same problem across the board. USE the DIC monitor to montior when the cylinder deactivates from 8 to 4 cylinders then press the gas slowly, thus the NOISE GM states to put the truck in manual mode to elimnate the kickdown on the (AFM) to eliminate the buffering sound. Anyone else think GM will try and fix this????

My 2015 Tahoe LTZ does the same thing. The buffering sound is attatched to the motor going from 8 to 4 cylinders. When you are crusing between 20 -60mph, let your foot off the guess for 2 seconds. The motor will switch into 4 cylinder mode, gently press accelerator and the noise will appear. I am getting a sqeaking noise also every time I press the accelarator during 20-60 mph, NOT GOOD!!