Shaking like a 70's car at a stop light.

[ghgmi]

Do these trucks have an idle air controller? Or does the ECU do everything through the main throttle?

[Robert.jean1]

If your trucks are doing that at low idle then one of your cylinders isn't firing. Unplug a spark plug wire on a engine and that will be the result. It could be anything as in fuel or spark but still there is now way a mechanic can say with any seriousness that it's normal. If it were normal nobody would buy these trucks.

[FL335i]

^Exactly. My truck has 28k on it. 5.3L. Smooth as glass. Once warmed up, in traffic, windows down a/c off... I can't even hear the engine. I have to check the tach. I would start with checking the MAF wire for cleanliness and cleaning the throttle body. Also make sure the air duct from the air box to the throttle body is properly installed and the clamps are all tight.

[jpmiami]

If the transmission is in neutral, does the shaking stop?

rpm's go up and it stops, it does it more when hot. if i just bring rpm's up by 100 its smooth again.

[jpmiami]

If your trucks are doing that at low idle then one of your cylinders isn't firing. Unplug a spark plug wire on a engine and that will be the result. It could be anything as in fuel or spark but still there is now way a mechanic can say with any seriousness that it's normal. If it were normal nobody would buy these trucks.

Thats the awser i got in 2 dealers ( they all do that) so live with it.

[jpmiami]

Mine used to do it before a custom tune, dealer said it was normal.

 

I had my tuner raise the idle RPM to 600 and now it never drops below when idling. And it is way smoother.

what tune did you get? It sucks that we need to spend $ to fix something GM could resolve very easily with out us risking voiding warranty.

[fondupot]

what tune did you get? It sucks that we need to spend $ to fix something GM could resolve very easily with out us risking voiding warranty.

Blackbear performance

 

 

Sent from my iPhone using Tapatalk

[crushNchowda]

You do realize it has a 6.2 liter lump of AL pushrod American V8 muscle thumping under the hood right?

The cam profile on these trucks aint like a mini 5.0 or 5.3 or V6, are you sure you're not just feeling the motor do its thing?

My LS1 GTO, L76 G8, LS6 Z06 all do the same. My 5.3 truck did not, my 6.2 truck does somewhat. Runs fine, definitely not misfiring.

[EChavez]

I have it too. Here's what I found. When stopped with the A/C was on, it would have this annoying shake that ran through the entire truck. When I turned the A/C off, the shake disappeared. I thought it was maybe an imbalanced pulley or a loose mount. I checked all that and nothing. I think it actually has to do with the RPM's. At certain RPM's, the shake presents itself. When I turn the A/C off, the RPM's rise just slightly, the the shake goes away.

Mine shakes too usually with the ac on but sometimes does it when it's off. I like driving with it on though because it makes my truck's exhaust louder lol. When it's off it sounds so girly.

[EPIC CAJUN]

Mine has been doing this since ive had the thing for a year now. 2 different dealers say its normal.

[iCryWheniGoPoop]

I'm curious as to what idle speed you are seeing when you get the shake? Is it lower than normal? Because if the engine cannon hold "target idle speed" there is a problem, period! I'm assuming the dealer is plugging in their scanner and verifying this.

 

My 6.2 has no shake, I would bet I can bring it down to 400rpm idle and still have no shake

 

 

Sent from Off Driller Side

[thomas poznanski]

I just got back from the dealer and I had the motor shims done didn't fix it. I bought a new tuner and raised the idle. I am from California so my thoughts are that these trucks come so choked down for emissions to meet federal laws that you are almost always forced to tune. I'm not sure but I do not remember any of my V8s idling below 500, after tuning your truck you will see a huge difference especially if you're in a California truck

[taylorcam11]

Just picked my 2015 4x4 LTZ Crew Cab up from the dealership yesterday after taking it in for its first oil change and rough idle. Mine was doing the same thing shaking very bad at a stop light. I got a very good technician and he explained to me that there is a service bulletin about this issue and explained to me how he fixed it. He explained to me that my engine was sitting a little unlevel and the service bulletin required shimming the motor mounts. He said that one side of my motor was grounding out agains the frame thus making my entire truck shake. He actually gave me a pico scope reading of before and after he shimmed the engine mounts. Mine was reading 3.6 micrograms before he shimmed and now its reading 2.2. I hope this helps!

[ghgmi]

All motors are grounded to the frame. I don't understand what you mean.

[taylorcam11]

Yes engines are grounded to the frame. But they have bushings that go on the motor mounts to reduce vibration and to ensure that its not metal on metal. Mine simply did not have enough support on one side of my motor so the technician installed shims to make my engine sit level and reduce felt vibration.