m3n00b

Sounds similar to my issue. Only happens sometimes.

My favorite brand is eBay Chinesium

Typical. You're going way too fast if you care at all about mpg. Anything over 70 kills it.

Probably this little guy ACDelco 22834330 GM Original Equipment Cabin Air Temperature Sensor Aspirator https://www.amazon.com/dp/B008B5TVC4/ref=cm_sw_r_cp_apa_i_R-dnEb430V469

Do the rpms climb slightly every few seconds when the shaking happens? Sounds like transmission stutter.

Try this. Solved it for me http://gm.oemdtc.com/492/transmission-adaptive-functions-and-correcting-low-mileage-harsh-shifts-2015-cadillac-chevrolet-gmc To Learn C1 (For 6-7 or 3-1 Shift) Pressure & Volume Learns: Note: It is recommended to utilize a road with a speed limit between of 30-45 mph (48-72 km/h) for this procedure. Shift the transmission into 6th gear with the PRNDM in the M position. Obtain an engine speed between 1000 and 1600 rpm. Maintain this condition for a total of about 5 miles (8 km). Cruise control may be used and has been found to result in faster learning of the clutch values Towards the end of the 5 miles I could feel the trans hunting around between 5-6 when cruising around 44mph. It's smooth as silk when coming to a stop now. Friggn computers.

You need to relearn the 3-1 shift. Let me dig up the fix. Busy at the moment.....

That number means absolutely nothing. What are you actually getting out of a tank? Have you measured your mpg by diving your mileage by the number of gallons you filled up with?

Hell yeah! Glad I could help. That sound drove me insane. It was so loud inside. I couldn't believe it.

Best of luck man! I want to say the wheels have 5" of backspacing and no spacers.

Nothing wrong with DexCool.

I'm also curious

The no wifi issue is because it's a 2016.

De-mudded and waxed

I didn't do the install. Here's a pic of the underside