Emissions Issue

[RAINCO]

7500 miles on my 2021 Sierra 1500 AT4 (5.3 V8). Driving down the highway and get what feels like the motor either missing or the transmission hesitating or very slight jerking. Subtle knocking. Slowly got worse on the way home. It appeared to be a little worse when I accelerated. When I got home I could step out of the truck at idle and heard knocking Popped the hood and heard the knocking a bit louder. He did not scare me but it was definitely peculiar and not normal. Moderately noticeable not deeply concerning other than the fact that it appeared to be coming from the motor.

dealership instructed to bring it in which I appreciate.
Check engine light came on and things gradually worsened on the way into the dealership but truck remain functional.

as I was checking in at the dealership I got an OnStar notification of an “emissions issue” detected. Instruto bring it in within the next seven days which suggests it is not critically urgent.

I had a Toyota decades ago that blew a head gasket and to say the least there were “emissions issues” - like white smoke blowing out of the tailpipe like a bonfire.

hopefully it can be identified and fixed and I’m not embarking on a chronic headache.

posting this in case others experience the same thing and in hopes of identifying the cause and communicating that out.

 

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[Frustrated Chad]

Hello
First time post. Want expecting to be looking for forums on a 2021 but go figure.

Purchase date : March 19 2021.
Miles once delivered to dealership 4.

1st check engine light occurred 2 weeks after driving off the lot. Took it in immediately. Service dept says no codes other than miss fires. In the shop for maybe 3 days.

2nd check engine light about May 26th (2 months after leaving the lot) same result. No codes other than misfires. In shop for 7 days. They replaced lifters and a temperature sensor.
June 3 pickup from shop, drove roughly 35 miles total that day from the dealership to the house. Next day on a 1.5hr drive for work (100 miles) On way back from the work trip got about 20min into heading back home, check engine light flashing, when trying to speed up from 65mph engine had very little power like it was sputtering/ no power. Got pulled over as quick as I could to avoid getting hit by big rigs. Killed motor and let it sit for 10min. Started back up and engine idling very rough, shaking whole truck(similar to old days of getting spark plug wires crossed on the distributor cap). Tried to Rev the engine a bit then 2 error lights and msgs popped up and did not go away. Lights were a P in a circle and Wrench as well as traction control symbol I believe. These lights with msgs service ecs and parking brake.

Truck in shop for 3rd time next day June 4th. Towed in by dealership from 70 miles away. I'm not having much of a warm fuzzy feeling with this new truck.

Total miles so far 3,456 (no joke)
Drove my 2007 sierra slt (2wd) crew cab for 15 years and never had any serious issues like this.

Not sure when I'm getting truck back this week and not sure I trust it. May be looking at a lemon possibly.

Sorry for venting just very frustrated.

 

[Frustrated Chad]

Picked truck up yesterday. Drove fine yesterday and all day today., actually felt more responsive, then again that could be hopeful thinking... coming home from dinner, check engine light on again. After getting the anger out in the cab, called my service agent and left vmail. Left a bit more of a poignant msg for the general service dept. Suggested the dealership owner be there when i bring it in tomorrow morning. Once I chilled a bit, hit the onstar button and asked them to run a diagnostic to try and capture a fresh/ new actual code. Hoping it worked, email shows P0300 which again is tied to miss fires. Unsure if this is same code they have been seeing in the shop. Wish I had done this last Friday since it had more error lights and actually had physical symptoms. This is beyond ridiculous. Dropping of in the morning on way to a work call if it makes it there. Will be calling a lawyer tomorrow as well to research my options.
This is my 4th vehicle ever in 34 years. Yes I drive my trucks for life. 2 Ford rangers 86 and 95, a sierra slt 07 (fully loaded display model for TMS race day) and now this one which I was hoping to be possibly my last vehicle ever. Maybe I got the covid AT4...

 

[Frustrated Chad]

So after last time in the shop. Apparently the GM engineers (lol) are on the case. It's a code issue.... drive the vehicle with the engine light on. Made it 1.5 days. Let my service guy know it's acting up again. Should I bring in? No drive it regardless(wtf)...
I sent txt and email asking for an official letter stating drive truck normal even with cel light on/ flashing at times now(that's new). No reply. Calling the gm for the dealership tomorrow. Give me a new truck and hoping it won't repeat the same issue. Sadly it will take months in sure to find the same options. Wife found another forum that seems to be more active with 3 others with same or similar issues. Class action maybe? This is such BS!

 

[Frustrated Chad]

Well latest update. Turned truck in week before last. Demanded a loaner. They had none... they ended up having to rent a vehicle from enterprise. Just did not feel safe driving a truck that could leave me stranded or worse late for a job. Got a call Wed this week that they have updated the computer and everything is good to go. Sadly I'm out of town. For a project. Can't get back to pickup until Saturday. I have never known of any engineer getting code updates out that fast, but we shall see.

 

[fngmoto]

Well latest update. Turned truck in week before last. Demanded a loaner. They had none... they ended up having to rent a vehicle from enterprise. Just did not feel safe driving a truck that could leave me stranded or worse late for a job. Got a call Wed this week that they have updated the computer and everything is good to go. Sadly I'm out of town. For a project. Can't get back to pickup until Saturday. I have never known of any engineer getting code updates out that fast, but we shall see.

Ugh that sounds like a freaking mess, sorry to hear it. Please keep us updated on what is going on if possible.

 

[Frustrated Chad]

Feels like the first week I bought the truck but still do not want to jinx it. Picked up truck sat before last. So far no CEL. Do notice some strange surges when stopping and taking off from an almost full stop which is probably the transmission. I have now seen several posts about that on other boards. A whole week with no cel, to early but I started looking at powered running boards again. Lol well see if we get 2 weeks in.

 

[Frustrated Chad]

Got to drive for almost 2 weeks after their computer code update and retraining the cam. Cel came back 1 day shy of a whole 2wks. Taking back in today or timepiece and see what the process is to have them replace it, buy back, whatever the options are. Really don't want engage a lawyer but may be only recourse. This sucks.

 

[Duramaximus]

None of this sounds very good. Please keep us posted on what you end up doing.

 

[Sith]

I have the same exact issue all of you have. Purchased mine in May, it’s been back to the dealership 4x for the same issue. Wasn’t until the last time at the dealership that they bluntly told me they have no clue what’s wrong with it, and that they worked with GM Engineers to try to figure it out, and they couldn’t. I was told they would continue to try to figure it out and let me know but I’m certainly not holding my breath.

 

[Frustrated Chad]

Latest update. Truck was in shop for 3.5 weeks. Think it was being used as a guinea pig by the GM engineers. App could not connect to it the whole time. Said there was something plugged into the diag port. Picked up today. Told to drive regardless of cel coming on. Per fm engineers. My karen(used to be a karen in her old days, not like the ones you see today but didn't take sh@t!) LOL we requested in writing that it was ok to drive with cel on. Denied. Told them we have lost faith in vehicle. I don't trust it if I have to travel for work. Mentioned buy back and lawyers. Got to see the dealership GM rep. Verbally agreed no issue if l
Cel comes back just keep them updated. Agreed. They are going to ask gm Corp to give us 72/100k for warranty. Plan b is if issue is still not resolved in a few months, vehicle swap basically. So we shall see how this goes. Just not looking forward to possibly getting lawyers engaged. Have me and the boss some piece of mind. As it stands we have had the truck in our possession 50%of the time since March. Want reviews on other vehicle models got me up. Acadia, numerous buicks, even a Tahoe that was an actual rental. Truck mfg date was last year so I think it was worked on by a mechanic building it with covid. Lol truck is sick just like the world today!

 

[LamboTexas]

Best of luck- hope everything turns out good for you!

 

[Duramaximus]

Crazyness! Please keep us updated.