Jump to content

2014 GMC 1500 5.3 uneven at idle

dtreid

By dtreid
in Engines & Drivetrain

 Share

Recommended Posts

dtreid Enthusiast

dtreid

Posted
Posted (edited)

When warmed up at a stop light, my truck is a little uneven at idle.  Does this mean that it is in V4 mode, or something else?

Edited by dtreid
Bob2C Enthusiast

Bob2C

Posted
Posted

Nope. It’s just GM’s crap idle. My 18 Tahoe did the same thing. Had motor mounts changed although helped did not solve problem. It idles to low. Got a diablo tuner and raised idle while in drive to 600. Smooth now.


Sent from my iPhone using Tapatalk

CamGTP Senior Enthusiast

CamGTP

Posted
Posted

The AFM is not active at idle or at low speeds, so it's not in V4 mode.

 

Some things may or may not help but are worth trying. You could try cleaning the MAF, the throttle body. If spark plugs have never been changed, maybe consider that. Try some fuel system cleaner for the injectors. Hard to say what it may be but 2-3 of those things are basically free to do.

 

Toss some premium fuel in the tank and go give it the business for a little while. I'll put a vehicle through the ringer sometimes just to get things cleared out and nice and toasty.

mookdoc6 Senior Enthusiast

mookdoc6

Posted
Posted (edited)

Nope,nope and another NOPE!  GM GDI hot idle mapped in Drive to 500rpm's about 100rpm's to low to be smooth...price you pay for GDI efficiency.  GM fuel economy on these V-8's are incredible it's give and take I choose to bump mine up 50rpm's in hindsight 100 would have been perfect. 

Edited by mookdoc6
Bob2C Enthusiast

Bob2C

Posted
Posted
Nope,nope and another NOPE!  GM GDI hot idle mapped in Drive to 500rpm's about 100rpm's to low to be smooth...price you pay for GDI efficiency.  GM fuel economy on these V-8's are incredible it's give and take I choose to bump mine up 50rpm's in hindsight 100 would have been perfect. 

Did you bump only in drive or when your in park as well? I just did in drive and left in park alone at 500. I was thinking of bringing that to 550. Annoys me but I don’t sit in the truck much while in park.


Sent from my iPhone using Tapatalk
BigBadSierra Senior Enthusiast

BigBadSierra

Posted
Posted

I've been using GDI IVD™ Intake Valve & Turbo Cleaner at every oil change and no idle issues ever.

 

This included the other direct injection engine like the 3.6 with 80K on it in the Impala that my mother brought to me complaining about the idle I cleared it up with the CDR.

 

It may take a few treatments to wash the valves off.

LDM Enthusiast

LDM

Posted
Posted
4 hours ago, BigBadSierra said:

I've been using GDI IVD™ Intake Valve & Turbo Cleaner at every oil change and no idle issues ever.

 

This included the other direct injection engine like the 3.6 with 80K on it in the Impala that my mother brought to me complaining about the idle I cleared it up with the CDR.

 

It may take a few treatments to wash the valves off.

Used this as well recently on my 18 as I noticed a bit of a rough idle at startup in the mornings.  It seems to have helped as I no longer have the rough idle since using it.

mookdoc6 Senior Enthusiast

mookdoc6

Posted
Posted
9 hours ago, Bob2C said:


Did you bump only in drive or when your in park as well? I just did in drive and left in park alone at 500. I was thinking of bringing that to 550. Annoys me but I don’t sit in the truck much while in park.


Sent from my iPhone using Tapatalk

No...the Park idle is fine 600rmps  Just bump the Drive idle...is all and your good!

  • 5 months later...
14burrito Enthusiast

14burrito

Posted
Posted (edited)
On 4/13/2020 at 6:14 PM, Bob2C said:

Nope. It’s just GM’s crap idle. My 18 Tahoe did the same thing. Had motor mounts changed although helped did not solve problem. It idles to low. Got a diablo tuner and raised idle while in drive to 600. Smooth now.


Sent from my iPhone using Tapatalk

 

So I have a stupid question, Can the idle RPM be changed without actually installing one of the canned tunes?

 

From my understanding, the features built-in to the inTune can only be used when installing one of the canned tunes (making alterations to that). Is this correct? Or can I hook up the inTune and make an idle RPM change and leave the OE file/Cal ID and such in the ECM?

 

 

Follow-up question, different train of thought...

 

I was told by a few that the vehicle can be flashed back to the OE file, take it to the dealer and they would not be able to tell if it had been flashed or not...I find this to be a little odd. Diablo could not answer this question...How is this possible?

 

Doesn't mode 9 clear/reset with a new SW file being flashed into the ECM? If so, all the dealer has to do is a systems health check, quick overview of collected data and it would otherwise shows X value erased/0 values...which in turn would bring the question of the dealer/GM network not showing a history of this from their side. I assume this would be standard practice for any and all warranty work especially powertrain related. Will they bother with this during a typical LOF, no. But I would assume they would research this depending on what warranty work would be getting completed.

 

Anyone have info about that?

Edited by 14burrito
Bob2C Enthusiast

Bob2C

Posted
Posted
 
So I have a stupid question, Can the idle RPM be changed without actually installing one of the canned tunes?
 
From my understanding, the features built-in to the inTune can only be used when installing one of the canned tunes (making alterations to that). Is this correct? Or can I hook up the inTune and make an idle RPM change and leave the OE file/Cal ID and such in the ECM?
 
 
Follow-up question, different train of thought...
 
I was told by a few that the vehicle can be flashed back to the OE file, take it to the dealer and they would not be able to tell if it had been flashed or not...I find this to be a little odd. Diablo could not answer this question...How is this possible?
 
Doesn't mode 9 clear/reset with a new SW file being flashed into the ECM? If so, all the dealer has to do is a systems health check, quick overview of collected data and it would otherwise shows X value erased/0 values...which in turn would bring the question of the dealer/GM network not showing a history of this from their side. I assume this would be standard practice for any and all warranty work especially powertrain related. Will they bother with this during a typical LOF, no. But I would assume they would research this depending on what warranty work would be getting completed.
 
Anyone have info about that?

Yes the idle can be changed. That was my original goal using the Diablo sport i3. I then decided to do a custom tune because I already screwed with the ecm so called “watermark”. From the numerous things I read even if flashed back to stock, GM can see the index marks don’t align with what is registered in their system for that vin and will deny warranty for power train issues. I couldn’t take the crap idle so I didn’t care.


Sent from my iPhone using Tapatalk
14burrito Enthusiast

14burrito

Posted
Posted
5 minutes ago, Bob2C said:


Yes the idle can be changed. That was my original goal using the Diablo sport i3. I then decided to do a custom tune because I already screwed with the ecm so called “watermark”. From the numerous things I read even if flashed back to stock, GM can see the index marks don’t align with what is registered in their system for that vin and will deny warranty for power train issues. I couldn’t take the crap idle so I didn’t care.


Sent from my iPhone using Tapatalk

Thank you, I will be sending a DM for a few points I would love to hear more from you about.

 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,760
    Total Members
    8,960
    Most Online
    MASONV88888888
    Newest Member
    MASONV88888888
    Joined

  • Who's Online   1 Member, 0 Anonymous, 1,634 Guests (See full list)

  • Latest Articles

  • Posts

    • Coastie05
      Replacing 2.7L on 2021 Silverado with 2023 2.7L

      By Coastie05 · Posted

      I’m definitely interested to hear the end result here. 
    • MASONV88888888
      Another 6.2L engine failure!

      By MASONV88888888 · Posted

      My 2025 Silverado 1500 had to receive a brand-new engine (long block) under warranty last month at only around 16,500 miles. Before the replacement, the truck repeatedly displayed "Engine Oil Level Low" warnings, even though the Oil Life Monitor still showed around 50% remaining after about 6,000 miles since my last oil change. After seeing the warning several times, I checked the dipstick with the engine cold, and the oil level was completely normal. The next day, the message escalated to "Add Engine Oil." At first, I assumed it was just a faulty oil level sensor, so I brought the truck to the dealership. After inspecting the engine, they found internal cylinder wall scoring and ultimately replaced the entire long block under warranty. Before this happened, I was planning to install a 4-inch lift and suspension upgrade on my truck. After needing a new engine at just 16,500 miles, I honestly don't see the point anymore. I also contacted GM to ask whether my vehicle qualified for a buyback, but I was informed that it does not at this time. Anyway, this experience has left me with serious concerns about the long-term reliability of this engine. I sincerely hope NHTSA expands the current investigation or recall to include 2025 model and performs a thorough inspection of affected vehicles. My biggest concern is that these engines may fail shortly after the powertrain warranty expires. If GM truly stands behind this engine, then at the very least, please consider extending the powertrain warranty to 10 years for affected owners. That would go a long way toward restoring customer confidence.
    • Grumpy Bear
      OCI, not when but why?

      By Grumpy Bear · Posted

      Without exception but then I'm the odd duck, right? I know what goes into that test, how it is calculated and thus how to beat it. But EPA values are often not beaten by the general public and the government has in past years adjusted the means and methods to come to those values to more closely approximate "Joe Average".    The only real trick to beating that EPA average is don't drive like "Joe Average".    It's the same method you used to profit from "Economic Migration" and in doing so beat the 'stats'. But you, like me, are not "Joe Average".     The thing you don't seem to grasp is this "Purchasing Power Index" isn't forward looking. It doesn't predict what it going to be but looks backward and states what it was. They are not telling us what the THINK, they are telling us what they MEASURED. Example:    Wife says "I'm going to lose 40 pounds by Christmas". May she does, maybe she doesn't but the doctors office who weighed her when she made that statement and again at Christmas only REPORTS what the RESULT was. You and I can banter about what was possible and what aunt Tilly did till the cows come home but the result is the result. Arguing otherwise is.....irrational. That's all I'm saying. This isn't about:      What you are calling a 'Statistic' is a RESULT not a CALCUATION and as a result the RULE. Like gravity as a rule, it can not be broken. 
    • MASONV88888888
      Rattle in the rear!

      By MASONV88888888 · Posted

      Just wanted to say thank you for posting this. Years later, your thread is still helping Silverado owners.   I bought my 2025 Silverado 1500 in January 2025, and I've had what feels like the exact same rattle since day one. After reading your findings, I believe my truck has the same issue with the cable carrier contacting the rear sliding window. To be honest, I had pretty much given up on pursuing the issue. It wasn't until I recently drove another brand's pickup that I realized just how quiet their cabin was—and how noisy mine has been all along. On my truck, the rattle happens on almost any paved road, gets even worse on rougher pavement, and I can even hear it during braking and acceleration.   I actually referenced your thread when submitting my case to GM, hoping they'll recognize this as a recurring issue instead of treating it as an isolated incident. The reason I reached out to GM first is because my dealership told me they would need to keep the truck for at least two days just to diagnose the problem. I was concerned that even after two days, they still might not be able to identify the source of the rattle before giving the truck back to me. I had also asked a few dealerships about this issue during previous service visits, but none of them seemed to know what was causing it or had a solution. That's why I decided to contact GM directly first, hoping they might already have an official repair procedure or guidance for this issue.   I also hope GM eventually comes up with an official fix for this problem. I have a feeling there are many Silverado owners experiencing the same rattle, but most either choose to live with it or simply don't know what the cause is.   Really appreciate you taking the time to document your diagnosis. Your post is still making a difference years later.
    • Buckwild27
      Gas Prices

      By Buckwild27 · Posted

      I have 2 choices. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...