2017 GMC Sierra Rough Idle problem

M7MDJUAN · February 2, 2018

Hello everyone,

I recently bought a brand new 2017 GMC Sierra Regular Cab 5.3 and i noticed when the car is idling there is a slight but noticable vibration from the dash and both seats, I sent it to the dealership and they said that this is normal which i can't believe so, and would like to know is it really normal and if anyone is experiencing same issue.

Also when i put the car in reverse the backup camera goes full brightness which blinds everything around me and i cant see anything from the mirrors.

Thanks.

MixerDriver · February 2, 2018

Any warning lights on? How many miles do you have on it? Sorry, but I probably won't be of help for your backup camera. Not too familiar with those.

M7MDJUAN · February 2, 2018

Thank you for replying,

There are no warning lights on, less than 4000km.

Aspen414 · February 2, 2018

No idea on the idling issue. The camera brightness issue is well known. There is, supposedly, a TSB out to fix it.

MixerDriver · February 2, 2018

Don't know just how rough your truck idles, but if you're running regular gas, maybe try running midgrade, just give it time to relearn for a different octane. My 2014 4.3 with 65k miles doesn't like regular 87 octane. Doesn't run bad on it, just not great. Switched to 89 midgrade, and she's a totally different truck. Runs smoother, MPG is marginally better, and seems to make a tiny bit more power. Definitely worth it for the extra $3 per fill-up. I also only run Top-Tier gas.

Still get a little rough idle every now and then. I attribute it to intake valve deposits from direct injection. Once every month or 2, I give her the old "Right Foot Tune-up" to clean it out. Hammer down getting on the freeway, then set the cruise at 75 in M4. Engine turns about 3k RPMs. I drive 10 miles to the next exit, and head home. After that, it idles smooth as silk, feels more responsive, and MPG gets a small bump. I also use Seafoam through the intake every other oil change, which works out to every 10k miles. However, I doubt you'd have enough buildup to cause major problems at such low mileage.

Sorry for the long winded response, but hopefully it's not totally useless info (:

M7MDJUAN · February 3, 2018

45 minutes ago, MixerDriver said:

Don't know just how rough your truck idles, but if you're running regular gas, maybe try running midgrade, just give it time to relearn for a different octane. My 2014 4.3 with 65k miles doesn't like regular 87 octane. Doesn't run bad on it, just not great. Switched to 89 midgrade, and she's a totally different truck. Runs smoother, MPG is marginally better, and seems to make a tiny bit more power. Definitely worth it for the extra $3 per fill-up. I also only run Top-Tier gas.

Still get a little rough idle every now and then. I attribute it to intake valve deposits from direct injection. Once every month or 2, I give her the old "Right Foot Tune-up" to clean it out. Hammer down getting on the freeway, then set the cruise at 75 in M4. Engine turns about 3k RPMs. I drive 10 miles to the next exit, and head home. After that, it idles smooth as silk, feels more responsive, and MPG gets a small bump. I also use Seafoam through the intake every other oil change, which works out to every 10k miles. However, I doubt you'd have enough buildup to cause major problems at such low mileage.

Sorry for the long winded response, but hopefully it's not totally useless info (:

Thanks for the reply, I am using the best tier fuel in my country which is 98 octane fuel so i dont think the fuel is the problem, but thanks anyways i will be checking with the dealership ship once again with a different agent to see the problem.