Newbie with 2016 Tahoe rough idle

[Vegas]

2017 Tahoe purchased new, started with a intermittent rough idle and strong vibration @ about 7000 miles. I took it in for an oil change and fuel gauge issue. They replace the fuel pump and said the idle issue must have been the fuel pump, as it isn't idling rough. I took it back as I had a oil leak after the oil change and told them the idle issue is still present. They fix the leak and said they could get it to idle rough, to drive it and see what happens. At about 7500 miles it stalled out and wouldn't start. It gave us an error code stating engine/transmission issue. Had it towed to the dealer. They replaced the fuel pump. It happen again a week later and died, then they replaced the fuel pump assembly. None of this fixed the original problem of rough idle/vibration problem. The vehicle has intermittent issues where you step on the gas it doesn't take right off and feels like it's going to stall and then it goes. The rough idle/vibration is only when in gear and stopped in traffic (note it doesn't do it every time and some times it less the others). My wife doesn't want to drive it, as she doesn't feel safe in it now. It's been in the shop about 30 days this year, with no fix of the original problem. Dealer is saying I have the upgrade motor mounts and there is nothing they can do. It now has 10,000 miles and idle/vibration is worse. I guess I need to contact GMC and see if they can do anything or try to see if I can get it handled under the lemon law. I will never purchase another Chevy, this is my first and last. :-(

 

[UFBeef]

I drove three different tahoe's when I purchased our 2015, everyone of them did this, as does a couple buddies. The only thing that has improved it for me was new plugs and wires. It still sits a bit low at idle while in D, but it is not that noticeable.

 

[Bob2C]

I have a 2018 Tahoe with 16k miles on it. I have the same rough idle in drive. I had the motor mounts replaced at 14k miles. Things were better for a bit but now the rough idle is back again but worse. I have no problems with acceleration or hesitation. I was thinking of just changing plugs and wires myself. I know this is quite a big problem amongst owners but no one really seems to know the root cause. I love the truck but the idle just annoys the crap out of me. I have never had a car idle like this before. Any new information on this subject would be greatly appreciated.

 

[Tk59194]

This may be a long shot, but worth considering. Direct injection is great, but what the engineers did not account for is the lack of fuel cleaning the back side of the valves. This has been a huge problem plaguing the VW and BMW communities. Induction service/walnut blasting is typically what those guys do to improve the rough idle associated with the carbon buildup on the intake side of the valves. Again, not saying this is the problem. I own a 16 Suburban and a 18 Tahoe. I had the valves serviced/cleaned on the SUBURBAN at 26K. I installed a dual valve catch can on my 18 Tahoe. It's amazing the amount of sludge it catches in just a very short amount of time. This sludge would be baking on to my valves if it weren't for the catch can. Once again, I make no claim that this is the solution. Only offering my experience

* both of my vehicles idle like new/no issues. YMMV

 

[sealandsky]

Hello everybody, I'm new here. I thought I'd skip the intro thread and go straight to the point. I apologize if the following topic has been beat to death, but I didn't see any recent enteries and I'm becoming very frustrated.

Here's the story:

Last summer we purchased a new black Tahoe LS. The car drove fine, but I was never happy with it since it wasn't exactly what I wanted, so I sold it. I then purchased a slate gray Tahoe LT with the luxury and destination packages from GM's Factory PreOwned Collection website. It's exactly what I wanted at a price I could afford. I took a chance on purchasing the vehicle(former rental) from across the country because I figured if there was anything wrong with it, it was still under warranty. Plus it only had 13k miles on it, so what are the chances something would go wrong with it.

WRONG!!!!! Rough Idle. The vehicle had a rough idle when stopped and in drive, such as being stopped at a stop sign or red light.

I took it to the Chevy dealer I used to go to and they gave me the runaround, and told me the rough idle was normal for that vehicle. I guess they forgot I previously had a 2016 Tahoe. That's why I "used to " go to them.

I took it to a different dealership, and they immediately mentioned a service bulleting regarding the engine mounts and shims. It seemed to help a little bit, but it was still there.

I took it back the following week and they changed the engine mounts completely, but called me back and said it was still idling rough. They told me they were going to scan it with a "picoscope" to determine where the vibration was coming from. Currently our Tahoe is still at the dealer because they had to order a longer censor for the picoscope. But based on all the stuff I've read on the internet, I don't expect too much. It seems like this issue isn't exactly uncommon with 2015-16 GM Suv's and trucks.

I'm very frustrated. i sold our new Tahoe with no issues and some equity, for a used Tahoe with issues, and now I'm upside down . The rough idle isn't horrible, but I feel like an idiot. I had no idea something like this could happen.

Anyone else experiencing something similar?

I'd experiment with something... While you are feeling the rough idle, try slipping the transmission in to neutral. Does the roughness go away? If so, you may be experiencing a slightly low idle setting. You might also try holding the brake with your left foot and giving the engine a tiny amount of power to see if that clears up the roughness. if so, then ask if the dealer can adjust the idle - Or replace / flash the ECM. the comment about air conditioning is along these lines as the idle speed is slightly increased when the A/C is turned on.

 

[Bob2C]

For me it doesn’t go away in park it’s just less noticeable. This is in park

Sent from my iPhone using Tapatalk

 

[chevypat]

The idle of my truck is around 400rpm which is pretty low compare to my other cars which is above 500rpm. When on neutral the rough idle goes away. From what I read on other posts is that the dealers cannot adjust the idle because it is a requirement from the factory to keep it at this specs. Maybe to lower the carbon footprint? Who knows. I miss the old days when you can just adjust the idle speed using a common screwdriver.

 

[gat0r]

^ get it tuned from BBP... they can raise it a hair. i did