Fixed rough idle

Obscenejesster · December 8, 2017

Figured I'd share this since I've seen a good amount of people here complain about a rough idle.

Personally, my '16 Silverado had a slight rough idle when sitting at red lights while the transmission is in drive. The RPMs would hover a notch below 500 and when the rough idle would kick in, you could see the RPM needle jump up and down. You would then feel a slight vibration through both front seats and if you had a cup of water in your center console, you could constantly see the surface of the water vibrating. It wasn't very bad but bad enough to see and feel it.

Two weeks ago, I decided to try this German made fuel injector cleaner called Liqui Moly. My local mechanic told me that no other cleaner could even come close to what Liqui Moly does and that it's all he uses.

I ran the Liqui Moly with 12 gallons of Premium gas from Shell. By the time half the tank was gone, I could immediately see the effects. Now two weeks later, I haven't had a single rough idle and the RPM needle stays pinned to 500 RPMs. The needle no longer fluctuates. The best part is that now, you can't even tell the engine is running. That's how smooth it is now.

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bdbake01 · December 8, 2017

Interesting. Where did you find it, or did you have to go online?

B R A D · December 8, 2017

Figured I'd share this since I've seen a good amount of people here complain about a rough idle.

Personally, my '16 Silverado had a slight rough idle when sitting at red lights while the transmission is in drive. The RPMs would hover a notch below 500 and when the rough idle would kick in, you could see the RPM needle jump up and down. You would then feel a slight vibration through both front seats and if you had a cup of water in your center console, you could constantly see the surface of the water vibrating. It wasn't very bad but bad enough to see and feel it.

Two weeks ago, I decided to try this German made fuel injector cleaner called Liqui Moly. My local mechanic told me that no other cleaner could even come close to what Liqui Moly does and that it's all he uses.

I ran the Liqui Moly with 12 gallons of Premium gas from Shell. By the time half the tank was gone, I could immediately see the effects. Now two weeks later, I haven't had a single rough idle and the RPM needle stays pinned to 500 RPMs. The needle no longer fluctuates. The best part is that now, you can't even tell the engine is running. That's how smooth it is now.

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I was wondering if I was the only one feeling the rough idle. Thanks for sharing!

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MaverickZ71 · December 8, 2017

What did the bottle say, and where did you buy it?

Ozer · December 8, 2017

probably this one?

https://www.amazon.com/Liqui-Moly-2007-Gasoline-Injection/dp/B00CPL8PSG/ref=sr_1_5?s=automotive&ie=UTF8&qid=1512751729&sr=1-5&keywords=liqui+moly+fuel+system+cleaner#customerReviews

Texas_Native · December 8, 2017

Glad I'm not crazy. I did a Google search for that Liqui Moly and looks like AutoZone carries it. Gonna go buy some today.

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Obscenejesster · December 8, 2017

I got mine from Auto Zone but you can also purchase it on Amazon.

My mechanic was telling me that the German Government is very strict in vehicle products. Before the product is even sold, it has to go through government testing to make sure it does exactly what it says it's going to do.

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B R A D · December 8, 2017

Not meaning to hi-jack in any way but Sea-foam is an outstanding product. I have been using it for years in my other vehicles. Google adding it through your intake, you'll be amazed at what it can do. It's just pure petroleum.

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Ozer · December 8, 2017

I use seafoam for small engines, outboards and such and it makes a difference.

I think this LM is easier and less messy, no white cloud and no need to change oil after treatment like seafoam requires.

B R A D · December 8, 2017

I use seafoam for small engines, outboards and such and it makes a difference.
I think this LM is easier and less messy, no white cloud and no need to change oil after treatment like seafoam requires.

You can add it to gas, oil or intake. I normally add it to gas but I have a 99 cobra mustang and I ran it through the intake and I was AMAZED at what that 32v motor blew out lol.

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fondupot · December 8, 2017

When I had my 2014 sierra, the only thing that fixed my rough idle was raising idle RPM to 600 with a Blackbear tune. Never had issues after that. 500 rpm is just too low.

mookdoc6 · December 8, 2017

18 minutes ago, fondupot said:

When I had my 2014 sierra, the only thing that fixed my rough idle was raising idle RPM to 600 with a Blackbear tune. Never had issues after that. 500 rpm is just too low.

Which is what I have to do too! the cleaning with moly ain't gonna do jack crap! it will rough idle until the Drive hot idle is same as PARK hot Idle......600 like fondupot says is probably the only way to go and with revised engine mounts they put out in 2016

gone_fishing · December 8, 2017

I raised my idle +50 RPM with my Diablosport intune i2 and that made the engine a lot smoother when sitting at a stoplight in gear with the AC on. In my opinion, GM just made the idle RPM too low.

sk · December 8, 2017

Seafoam is pretty good stuff.

Liqui Moly is a little better.

If you want an even better clean use BG 44K.

https://www.bgprod.com/catalog/gasoline-fuel-system/bg-44k-fuel-system-cleaner/

If you want an amazing clean get a BG fuel/air induction system clean done by a certified shop. It uses special pressurized equipment to force the cleaner through all the orifices in the engine.

https://www.bgprod.com/services/gasoline-fuel-services/gdi-fuelair-induction/

Edited December 8, 2017 by sk

Obscenejesster · December 8, 2017

Seafoam is pretty good stuff.

Liqui Moly is a little better.

If you want an even better clean use BG 44K.
https://www.bgprod.com/catalog/gasoline-fuel-system/bg-44k-fuel-system-cleaner/

If you want an amazing clean get a BG fuel/air induction system clean done by a certified shop. It uses special pressurized equipment to force the cleaner through all the orifices in the engine.
https://www.bgprod.com/services/gasoline-fuel-services/gdi-fuelair-induction/

I was actually told that GM recommends the BG service every 15k miles on GDI engines.

Is there any truth to this? I have heard that it is very good for GDI engines.

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