2012 Chevrolet Suburban 4x4 LT 5.3L

[Topkicker]

Purchased new 2012. Perfect vehicle. Just normal maintenance items. All maintenance has been completed as it came due through the years. Truck still looks and sounds brand new. Currently 187,000 miles. No CEL. No lights at all. Last week started getting skip/flutter in any range, seems worse under load. When it stutters or flutters the RPM gauge flicks for a few seconds too. However,It will sit and idle perfect. First thought it could be a gas issue and ran the tank to empty. Refilled with premium and Redline fuel treatment. No change. 
72 month Interstate Mega Tron Plus installed Jan. 2018, tests good.
Plug and wires replaced 100,000 miles. 
Only odd thing is my voltage meter is reading over 14.??

Thoughts on something this noticeable but no warning lights?

[richard wysong]

Spark plugs are nearing the end of their service life so I would start there or get a scan tool that does live data and look at misfire counts, could be 1 of the coils is going bad or an injector is clogging. Voltage is within specs so I wouldn't think that is related

[Topkicker]

Thanks, what is a dependable scan tool that does live data in your opinion ? I have been putting off buying one but I am ready to move ahead now. All Chevys in the household, 2014 Impala, 2017 Silverado 1500, and at some point a GMC Yukon XL. 

[swathdiver]

32 minutes ago, Topkicker said:

Thanks, what is a dependable scan tool that does live data in your opinion ? I have been putting off buying one but I am ready to move ahead now. All Chevys in the household, 2014 Impala, 2017 Silverado 1500, and at some point a GMC Yukon XL. 

GM MDI with GDS software on a laptop.  Will service all vehicles. mentioned.  Tech-2 for the 2012.

 

Voltage charging high all of the sudden and all of the time is the sign of a wore out battery.

Edited February 19, 2023 by swathdiver

[Topkicker]

Thanks for the info on GM software. Going to move forward with that.
Changed the spark plugs.  It was time. Didn’t not correct the issue. I am going to replace the battery this week. 

[CamGTP]

The 6L80e's have torque converter issues after lots of miles. The flutter of the RPM could be the torque converter locking/unlocking and slipping. You'd need a really nice scan tool to watch the torque converter clutch readings for the commanded lockup, desired slip and actual slip speed.

 

This is just a guess at the issue.

[Topkicker]

Alternator and battery all good after load test. Scan tool indicates issue is in the remote sense wire coming off the alternator. You can remove that off the alternator and voltage meter inside truck goes back to 14 just like it always has been and the intermittent flutter goes away. Looks like some wire tape and loom is coming off tomorrow. Anyone seen this before? Any tips?

[swathdiver]

Are you aware of the term, Regulated Voltage Control?  Our alternators are controlled by the BCM, think of the charging system as a smart charger for an RC battery pack.  If you disconnect the battery current sensor, the alternator will revert to a standard output which does not help battery life.

 

What codes did the scan tool reveal?

[richard wysong]

Seems to still be pointing to a battery issue