Low frequency vibration under light load when AFM kicks in - 1500/5.3L

[ember1205]

2015 Silverado 4x4 Crew Cab w/ the 5.3L V8 gas only. 90k miles on the truck.

 

When AFM kicks in and it drops to V4 mode, there is a very slight vibration that can be felt. If you press the accelerator a bit to add load, but not enough to switch it back to V8 mode, it will intensify a bit. This started in the last 5k miles.

 

Recent oil and filter change yielded expected amount of waste oil (not burning) with expected color and such as well. Didn't seem to show any signs of any material or contaminants.

 

Given the age and mileage, I'm wondering whether it's worth changing the plugs and wires to see if it might be related since those are recommended to be swapped at 100k. Or, is this a more well-known thing where I should be looking elsewhere?

Edited February 9, 2022 by ember1205

[CamGTP]

Could be torque converter related.

[ember1205]

11 minutes ago, CamGTP said:

Could be torque converter related.

Interestingly, I had something else occur (a "barking" squeak under certain conditions when accelerating) a few thousand miles ago that I thought was a transmission issue. Had it checked at the dealer and they ran diags on everything in the trans... All clean. The noise was coming from the mechanical valve in the exhaust, right in front of the muffler. Completely unrelated to this...

[Mac McKenzie]

I've noticed this on my 2013 5.3.

Being as I bought it used, I thought it was normal.

[ember1205]

32 minutes ago, Mac McKenzie said:

I've noticed this on my 2013 5.3.

Being as I bought it used, I thought it was normal.

Different generation of the motor and such, though, so hard to know what sort of parallels there might be.

[silveradosid]

my truck started doing that at 45k, got a range device , i am at 153k now