MiPinner

Thanks for the response. Have I tested the flapper, yes. I used a piece of wire and tested both open and closed. Same results. The knock is only recorded when in 4v mode. I am monitoring PID - Displacement on Demand Request and as soon as it flips to YES, the knocking starts. It's pulling about 4 degrees. While running in v8 mode there is no knock.

We have a 2016 Yukon 6.2L which developed a rattle at approximately 60k miles. Initially I believed the source of the rattle was a heat shield, but everything seems to be tight. It has been to the dealer twice and no progress has been made to resolve the issue. The first time they dismissed the problem and called it "normal" and the second time they believe it's a broken baffle weld in the muffler. What do you think? Thanks in advance Video with several angles from under the vehicle demonstrating the issue. The problem only surfaces when the vehicle inters v4 mode. Also, the rattle is so loud it is picked up by the Knock Sensors and it pulling timing. Scan performed with HP Tuners VCM Scanner.