2025 Tahoe 6.2-liter Z71 engine light flashing, stuttering engine

[ChevyFan47]

My 2025 Tahoe Z71 6.2-liter had less than 700 miles on it when the engine light started flashing and the engine stuttered/fluttered/hiccups at any speed. This is an intermittent problem. The dealership has twice tried remedy this by checking which cylinder is misfiring, but each time I've gotten it out of the shop, the trouble starts again within a day. Help! This is a troubling situation. The truck is brand-new. Is this even fixable?

 

[pa31p]

You pretty much have to rely on the due process/troubleshooting by dealer to fix it. the good news is they will fix it one way or another. yes frustrating! but it does happen. so give them some time to actually do troubleshooting. if they don’t fix it 100% there’s multiple other options. for now, let them do their job.

Could be as simple as a coil or sparkplug or connector loose. CEL flashing usually misfire of somesort.

 

[ChevyFan47]

You pretty much have to rely on the due process/troubleshooting by dealer to fix it. the good news is they will fix it one way or another. yes frustrating! but it does happen. so give them some time to actually do troubleshooting. if they don’t fix it 100% there’s multiple other options. for now, let them do their job.

Could be as simple as a coil or sparkplug or connector loose. CEL flashing usually misfire of somesort.

Thank you so much.

 

[Carfan]

Is there another dealer nearby?

 

[Fless]

So if they "fix" it for a day, what are they telling you was the cause?

I might be mistaken but you may be able to use a Cadillac or any GMC dealer for warranty work.

 

[ChevyFan47]

Is there another dealer nearby?

Yes. I bought it in another city and am returning there to that dealer.

 

[ChevyFan47]

So if they "fix" it for a day, what are they telling you was the cause?

I might be mistaken but you may be able to use a Cadillac or any GMC dealer for warranty work.

They’ve said it was a coil and a bad seal and spark plug. None of that has fixed it. I’m wondering if there is some factory flaw in the new models.

 

[tom3]

Probably 25 different things that could cause that condition. Is it always the same cylinder mis-firing?

 

[ChevyFan47]

I don’t know. They said it was same one but I’m not confident they did much.

 

[2024 White Tahoe]

I don’t know. They said it was same one but I’m not confident they did much.

What did the warranty repair invoice for the repair(s) state was done?

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

 

[jfoj]

Flashing SES/CEL/MIL usually means misfiring, which appears you felt in the vehicle.

Some common causes are fuel injectors, ignition components, fuel delivery and even the low pressure Fuel Pump Control Module being intermittent.

The dealer or anyone with an OBDII tool should be able to obtain the OBDII codes and what is really KEY is the Freeze Frame Data. Even if the vehicle is new and under warranty, EVERYONE needs their own OBDII scan tool. A reasonable option is OBDFusion for your phone, $10 max. The buy an interface like this on Amazon for $32 or less if there are discounts - https://www.amazon.com/gp/product/B073XKQQQW/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

This way you can gather your own data, sometimes helpful for the repair shop and will allow you to know what may be the culprit.

I keep an interface in ever one of my vehicles.

 

[WalleyeMikeIII]

Next time the CEL is flashing, hit OnStar and ask for the remote diagnostics. Hopefully this will get you the codes w/ what cylinder is MisFiring. That said, I’d think the history code would give the actual cylinder or cylinders that are misfiring.

 

[ChevyFan47]

Probably 25 different things that could cause that condition. Is it always the same cylinder mis-firing?

It is "cylinder 4," whatever that is. They removed and relocated the spark plug, coil and plug wire to different cylinders. Then test drove it and found that it stayed on cylinder 4. They did some other stuff like inspecting lifters and camshaft and valves. The "valve sets" were not sealing. They installed a cylinder head and cleared codes and test drove it. Worked fine. Next day I got and the misfire was back.

 

[StephenPT]

It is "cylinder 4," whatever that is. They removed and relocated the spark plug, coil and plug wire to different cylinders. Then test drove it and found that it stayed on cylinder 4. They did some other stuff like inspecting lifters and camshaft and valves. The "valve sets" were not sealing. They installed a cylinder head and cleared codes and test drove it. Worked fine. Next day I got and the misfire was back.

I'm surprised they didn't swap the #4 injector with a different cylinder... Misfire can be from an issue with air, fuel and/or spark. Sounds like they've dealt with air and spark, but not fuel.

 

[MAThree]

My 2025 Tahoe Z71 6.2-liter had less than 700 miles on it when the engine light started flashing and the engine stuttered/fluttered/hiccups at any speed. This is an intermittent problem. The dealership has twice tried remedy this by checking which cylinder is misfiring, but each time I've gotten it out of the shop, the trouble starts again within a day. Help! This is a troubling situation. The truck is brand-new. Is this even fixable?

Did you ever find a fix? I have the exact same issue, buts on cylinder 3. I’ve had it changed 2x already and it’s still doing the same thing. Brand new 2025 High Country Tahoe. I’m up to 7000 miles, but it’s been doing it the entire time I’ve had the vehicle.

 

[Antonm]

Sorry I can't provide any insight on your issue other than to keep taking it to the dealership for repair.

But side note,,, did you special order your Tahoe or something?

Before I bought the High Country I was specifically looking for a Z71 (or GMC AT4) with the optional 6.2 engine. The GM website's new inventory section literally listed one (and only one) anywhere in the country, and it was like 2000 miles from me. So we settled on the High Country (didn't like the Denali dash configuration with the center screen being so far down) because HC's were everywhere and readily available (like our local dealership had four HC's in stock at just that one location)
...

 

[viven44]

Would be interesting to see what the outcome is... With the 6.2L, just because its a 2025, I wouldn't rule out the infamous crankshaft "manufacturing defect" that affected 2021-2024.. They really need to run the "picoscope test" to rule out the possibility of that kind of problem. We've seen a few cases here in the past year of phantom/intermittent stumbling, shutdown issues that look like an ignition or fuel problem, but end up needing full engine replacement.

 

[KTBear]

I've been reading alot of the posts because I seem to have a similar issue. History: In July 2025, I bought a 2019 GMC Yukon Denali 6.2L (I named the vehicle Barney - no nasty comments please) with almost 49,000 miles on. Bought it at a GMC dealership way, way across town (about 2 hours from home). Bought the extended warranty with it. (I'll also add at this time, I have not put 5,000 miles on it.) I live north of Atlanta (this really doesn't have any point to the post - just reference). I work from home so I really don't drive except around town and my occasion road trip. I have driven Barney down to Destin, FL twice and to Ocean City, MD. Prior to driving to Ocean City, I noticed it was running alittle rough. I knew we were going to be doing highway miles, I put some fuel injector cleaner in the gas tank thinking maybe because of the around town driving spark plugs were fouled. By the time we got home, still running rough. One morning as I was driving home from visiting my brother in the hospital the rough got ROUGHER! Next thing I knew the front collision alert came on the dash, then the traction control orange light came on and the engine light started flashing. I was very close to home (less than 3 miles) got it in the driveway and parked it so a rollback could pick it up. Rollback picked it up and took it to my closest Chevy dealer (the GMC dealer did tell me I could take it there). They did the diagnostics on it and said that its ignition coil #6 that was causing the problem. So they replaced it. Picked it Thursday night, drove it back to the hospital to see my brother and not even 10 miles in the drive, started running rough again! Drive it home that night and parked it. Drove it to the chevy dealer Saturday morning, they put the code reader on it and said "oh its ignition coil #2." So once again they replaced another coil. Once again I pick it up and within 25 miles it starts running rough again. Back I go with it, this time I ask for the service manager to get involved because this is the 3RD time for the same thing in less than 30 days. Coils shouldn't be going bad like this, there's something that we're missing, there's an underlaying problem we're not looking at. Is it something in the fuel system, maybe a fuel injector, (and I literally said this) could it possibly be a faulty spark plug. . . . . there's something we are missing. Can something please be the Monday morning quarterback on this and really look into it? Of course, they said yes. A few days later they call to say they can't find anything. I asked if they drove it. . . . .we drove it in the parking lot. I gave them authorization to drive it and they did 30 miles. And once again they told me they couldn't replicate the problem. That it was ready and I could pick it up. In addition to the running rough, it feels like its "surging" . . . .like it wants to go faster but I'm holding it back. So needless to say (after my long winded explanation) my "I was so excited about my new to me vehicle" running rough and I have no clue. I guess I just wait for it to break down or the engine light to flash.


Vehicles I own:
2002 Chevy Silverado LT 2500HD, 4WD, 8.1L Allison Transmission - Gas (black in color)
2003 Chevy Tahoe Z71, 4WD, 5.3L - Gas (black in color)
2009 VW New Bettle Convertible - Gas (triple black in Color)
2019 GMC Yukon Denali, 4WD, 6.2L - Gas (black in color
1964 Pontiac GTO, 389, 4-speed - Gas (saddle bronze metallic)

 

[KMeloney]

I've been reading alot of the posts because I seem to have a similar issue. History: In July 2025, I bought a 2019 GMC Yukon Denali 6.2L (I named the vehicle Barney - no nasty comments please) with almost 49,000 miles on. Bought it at a GMC dealership way, way across town (about 2 hours from home). Bought the extended warranty with it. (I'll also add at this time, I have not put 5,000 miles on it.) I live north of Atlanta (this really doesn't have any point to the post - just reference). I work from home so I really don't drive except around town and my occasion road trip. I have driven Barney down to Destin, FL twice and to Ocean City, MD. Prior to driving to Ocean City, I noticed it was running alittle rough. I knew we were going to be doing highway miles, I put some fuel injector cleaner in the gas tank thinking maybe because of the around town driving spark plugs were fouled. By the time we got home, still running rough. One morning as I was driving home from visiting my brother in the hospital the rough got ROUGHER! Next thing I knew the front collision alert came on the dash, then the traction control orange light came on and the engine light started flashing. I was very close to home (less than 3 miles) got it in the driveway and parked it so a rollback could pick it up. Rollback picked it up and took it to my closest Chevy dealer (the GMC dealer did tell me I could take it there). They did the diagnostics on it and said that its ignition coil #6 that was causing the problem. So they replaced it. Picked it Thursday night, drove it back to the hospital to see my brother and not even 10 miles in the drive, started running rough again! Drive it home that night and parked it. Drove it to the chevy dealer Saturday morning, they put the code reader on it and said "oh its ignition coil #2." So once again they replaced another coil. Once again I pick it up and within 25 miles it starts running rough again. Back I go with it, this time I ask for the service manager to get involved because this is the 3RD time for the same thing in less than 30 days. Coils shouldn't be going bad like this, there's something that we're missing, there's an underlaying problem we're not looking at. Is it something in the fuel system, maybe a fuel injector, (and I literally said this) could it possibly be a faulty spark plug. . . . . there's something we are missing. Can something please be the Monday morning quarterback on this and really look into it? Of course, they said yes. A few days later they call to say they can't find anything. I asked if they drove it. . . . .we drove it in the parking lot. I gave them authorization to drive it and they did 30 miles. And once again they told me they couldn't replicate the problem. That it was ready and I could pick it up. In addition to the running rough, it feels like its "surging" . . . .like it wants to go faster but I'm holding it back. So needless to say (after my long winded explanation) my "I was so excited about my new to me vehicle" running rough and I have no clue. I guess I just wait for it to break down or the engine light to flash.


Vehicles I own:
2002 Chevy Silverado LT 2500HD, 4WD, 8.1L Allison Transmission - Gas (black in color)
2003 Chevy Tahoe Z71, 4WD, 5.3L - Gas (black in color)
2009 VW New Bettle Convertible - Gas (triple black in Color)
2019 GMC Yukon Denali, 4WD, 6.2L - Gas (black in color
1964 Pontiac GTO, 389, 4-speed - Gas (saddle bronze metallic)

Welcome to the forum.

You COULD be experiencing the same problem in your '19, but just be aware that this is the '21+ section. There may be solutions to your specific year truck in the pre-'21+ section.