RPM fluctuating

[mookdoc6]

Mine does it although not as noticeable as much....Had a fast learn and C4 Clutch pack adj.....

[vacuman]

I've also noticed the tach fluctuate slightly at around 50-55mph with a change in exhaust note. It goes away when speed increases. It doesn't seem to be a real problem, but if it is, I want it fixed before the factory warranty expires. Trans fluid is level is right on and only has about 16K miles on it.

 

2015 Sierra 5.3L 6spd

[GMC-AT]

http://gm.oemdtc.com/6597/pip5337e-shake-or-shudder-on-acceleration-excessive-engine-rpm-fluctuation-between-30-and-65-mph-2015-2016-cadillac-chevrolet-gmc

 

See link above... I'm guessing your issue is only below 1500 RPM. Mine did it on one trip.. right about 60-65mph.. 1300rpm. Once I got above 1500 - around 72mph.. it never did it. I would also get a shake and shutter when it happened.

 

My issue was a little more harder to pin down because I got a tune the same time it happened. Anyway.. I re-installed the tune and it never happened again. I still see the RPM bounce a little bit around 50-60mph.. but I get no shutter....so it's all good.

[Broman504]

What if the fluctuation is at idle? Like in park? Anyone know what this is about? If i give it throttle in park it stays at that rpm until i turn my truck off. Please help..... this truck was too expensive for all this crap. Hahaha

 

Edited April 30, 2021 by Broman504

[JimCost2014]

21 minutes ago, Broman504 said:

What if the fluctuation is at idle? Like in park? Anyone know what this is about? If i give it throttle in park it stays at that rpm until i turn my truck off. Please help..... this truck was too expensive for all this crap. Hahaha

 

Welcome to the site.

 

How about a little more info about your truck. Looks like you are over 100000 miles, so my guess would be your torque converter is having issues.

[silveradosid]

doing it in park has nothing to do with the converter, at 100k have you even cleaned the throttle body

[Anthony Pavarini]

I am having the same issue as Broman504.

2016 GMC Sierra 1500 Denali 4X4 about 111,750 miles.

Stuck lifter so just finished rebuilding the engine.
BTR Stg1 cam; New HPFP; all new GS7 lifters; stock rockers with CHE grunion upgrade; VVT limiter; removed mechanical vacuum pump. Gibson shorty headers just cuz; Custom tune to turn off AFM plus getting the most out of the engine.

My RPN flutter happens while in dark and I move the steering wheel. A couple of times she stalled, but mostly it just settles down

[Steven Jankowski]

May have found an easy fix for some issues of surging, growling with rpm fluctuations, battery gauge only indicating battery voltage, and NOT inducating alternator voltage of 14 vokts, etc. Worth a try. 

-Turn ignition key OFF

-disconnect battery pos. Cable from battery POST.

- Turn ignition key to just before start.

-Allow to set disconnected with key in just before start position for a minimum of 15 minutes 

- After 15 minutes, Turn ignition key to OFF

- Reconnect pos battery cable

Turn ignition key to just before start; DO NOT START VEHICLE!

I got a message to open, and then shut driver's side window. System reset itself.

No more surging, growling, etc.