2017 5.3L/8 speed lugging at throttle tip in

Kubs · February 28, 2018

So... I just ordered a '18 5.3L with an 8 speed (max trailering package) and now I see this thread. I read everything from start to finish and it seems like a fuel issue. Either injectors not working properly, or the factory tune trying to save fuel and not using enough when needed. I hope I don't regret my purchase, but if this issue comes up and the dealer gives me a hard time it sounds like I can tune it out myself.

Regarding a tune, I understand a handheld tuner may not be able to remedy the problem but a tuner shop with a dyno can still get enough access to the TCM? Fortunately we have one of the best LS tuners in the country here in Ohio. I hope they are able to do the K2 platform as well.

SGS_Z71 · February 28, 2018

4 hours ago, Kubs said:

So... I just ordered a '18 5.3L with an 8 speed (max trailering package) and now I see this thread. I read everything from start to finish and it seems like a fuel issue. Either injectors not working properly, or the factory tune trying to save fuel and not using enough when needed. I hope I don't regret my purchase, but if this issue comes up and the dealer gives me a hard time it sounds like I can tune it out myself.

Regarding a tune, I understand a handheld tuner may not be able to remedy the problem but a tuner shop with a dyno can still get enough access to the TCM? Fortunately we have one of the best LS tuners in the country here in Ohio. I hope they are able to do the K2 platform as well.

Overall, I still love the truck, that’s what has been hard. I did not want to get rid of it. I can say as long as it stays like it is now, I’m good. I loved my truck from 0-5000 miles, and then it went south from there and I got very bitter. I will have it tuned down the road though as it just does some funky crap every so often, but so did my 14’ Sierra 4.3/6 speed. Who is the tuner you mention, I haven’t looked yet? Follow the thread, I will post on it over time if any more issues pop up. Trying to get as much google hit words as possible so this can potentially help people get their trucks straightened out. A lot of this resolution comes down to the dealer, they had to do actual mechanic diagnosis versus “no code, no problem”. It sounds like some of these guys have some bad ones. I am mostly happy with mine. On my open case with GM, I have asked them to extend my powertrain warranty because it would have been running lean for 7k+ miles. Who knows if that detonated/pinged and damaged pistons.

SGS_Z71 · February 28, 2018

6 hours ago, 13891 said:

Thanks for the info. Not sure if they will do anything yet.

No problem, if you end up needing that dealer, let me know. With my open case with Gm, trying to minimize parties involved. Keep the thread updated with your progress. If they won’t help you, open a case with GM and/or go to a different dealer.

Kubs · February 28, 2018

36 minutes ago, SGS_Z71 said:

Overall, I still love the truck, that’s what has been hard. I did not want to get rid of it. I can say as long as it stays like it is now, I’m good. I loved my truck from 0-5000 miles, and then it went south from there and I got very bitter. I will have it tuned down the road though as it just does some funky crap every so often, but so did my 14’ Sierra 4.3/6 speed. Who is the tuner you mention, I haven’t looked yet? Follow the thread, I will post on it over time if any more issues pop up. Trying to get as much google hit words as possible so this can potentially help people get their trucks straightened out. A lot of this resolution comes down to the dealer, they had to do actual mechanic diagnosis versus “no code, no problem”. It sounds like some of these guys have some bad ones. I am mostly happy with mine. On my open case with GM, I have asked them to extend my powertrain warranty because it would have been running lean for 7k+ miles. Who knows if that detonated/pinged and damaged pistons.

The dyno is Backstreet Performance in Medina, OH. They do awesome work on Corvettes and LS swaps.

I am going to keep and eye on this thread and add any experiences I have to it. I am thinking after a year I will add a catback and larger tires, etc and do a dyno tune at that time, regardless if I am having issues with lugging or not.

MD11G200 · March 1, 2018

On 2/28/2018 at 8:24 AM, Kubs said:

So... I just ordered a '18 5.3L with an 8 speed (max trailering package) and now I see this thread. I read everything from start to finish and it seems like a fuel issue. Either injectors not working properly, or the factory tune trying to save fuel and not using enough when needed. I hope I don't regret my purchase, but if this issue comes up and the dealer gives me a hard time it sounds like I can tune it out myself.

Regarding a tune, I understand a handheld tuner may not be able to remedy the problem but a tuner shop with a dyno can still get enough access to the TCM? Fortunately we have one of the best LS tuners in the country here in Ohio. I hope they are able to do the K2 platform as well.

Cancel your order, the transmissions are junk. I have a 2017 6.2 8 speed 4X4 SLT loaded, one notch under a denalli, most powerful, quietes and,smoothest riding truck(on the interstate) I have ever owned but also the biggest piece of around town klunky klunky junk I have ever driven for what i paid, buy a F250 diesel only truck on market I know of with no klunky transmsion problems( 2 guys in my club had same problem and traded for them). My 400HP 1979 Chevrolet blazer with 36s drives better around town, yes the 8 speeds are that bad

Kubs · March 1, 2018

I havn't heard they are junk, just a few issues here and there. I also wouldn't go fo far as to cancel my order. I just wanted to see what I was up against regarding this issue. It also seems to be hit or miss because I know several people who are happy with their purchase and not having any issues in 50k+ miles. I would rather have a Chevy with a clunky transmission than ever own a Ford! lol

March 2, 2018

On 2/28/2018 at 12:49 PM, SGS_Z71 said:

No problem, if you end up needing that dealer, let me know. With my open case with Gm, trying to minimize parties involved. Keep the thread updated with your progress. If they won’t help you, open a case with GM and/or go to a different dealer.

Dealer called today and will be scheduling an appointment to test injectors. I’ll keep you posted.

SGS_Z71 · March 12, 2018

On 3/1/2018 at 10:32 PM, 13891 said:

Dealer called today and will be scheduling an appointment to test injectors. I’ll keep you posted.

Any update??

BamCam · March 12, 2018

11 hours ago, SGS_Z71 said:

Any update??

Are you still happy with your fix? Just curious what your avg mpg is? Was it ever below 15mpg during issues?

My brother's truck is now only getting 12-13mpg combined. Before his issues at around 5000 miles he could easily get 19-22mpg. He is still awaiting lemon law results so no repairs or attempts are being performed at this point.

SGS_Z71 · March 12, 2018

12 minutes ago, BamCam said:

Are you still happy with your fix? Just curious what your avg mpg is? Was it ever below 15mpg during issues?

My brother's truck is now only getting 12-13mpg combined. Before his issues at around 5000 miles he could easily get 19-22mpg. He is still awaiting lemon law results so no repairs or attempts are being performed at this point.

I am mostly happy. I still feel the chuggle every now and then, which is just an annoyance. The loaners I had all had it as well. I average 20-21 on the highway, combined getting around 17. Never saw any difference either way.

If I can get any chuggle to repeat on command, it will go back in for sure. I have zero tolerance for issues with this thing. It will chuggle for a second for two while tipping into the throttle under load, before it figures out what it is supposed to do.

Planning on a lot of towing this season, that will make or break it.

SGS_Z71 · March 13, 2018

Well, I spoke too soon. My hestitation is back! On the way home from Chicago, started doing it more and more. Took it out today, and it is still doing it. Back to the dealer I go.

Running the numbers on how much pain I will face to get out of this thing.

Dnt · March 14, 2018

17 6.2 8spd approx 15k miles. I had the trans reflash done several thousand miles ago and it is better, I really doubt that the majority of drivers would ever have even have noticed the slight lag or harsh shifting. Some people (car people like me) are a lot more sensitive to imperfections. Just seems that the GM trans programming and torque management system are set up for fuel economy and nothing else. I am OK with it for now, after all it is NORMAL LOL and it does get great gas mileage.....

BamCam · March 14, 2018

19 hours ago, SGS_Z71 said:

Well, I spoke too soon. My hestitation is back! On the way home from Chicago, started doing it more and more. Took it out today, and it is still doing it. Back to the dealer I go.

Running the numbers on how much pain I will face to get out of this thing.

Man that sucks! What are you looking to get?

From our experience all the loaners had this same issue or slightly less but it appears to be a gamble that in 5K miles your not in the same boat. My brother is looking to move away from a pickup for awhile. He feels (I would agree) that manufacturers are just trying too hard (no fault of their own) to get these bloated pigs down the road within CAFE requirements. It is a shame because the trucks are really nice otherwise.

SGS_Z71 · March 14, 2018

15 minutes ago, BamCam said:

Man that sucks! What are you looking to get?

From our experience all the loaners had this same issue or slightly less but it appears to be a gamble that in 5K miles your not in the same boat. My brother is looking to move away from a pickup for awhile. He feels (I would agree) that manufacturers are just trying too hard (no fault of their own) to get these bloated pigs down the road within CAFE requirements. It is a shame because the trucks are really nice otherwise.

I have to have a truck, as I tow a camper, etc. Really bad timing as I about 6 weeks before a first trip. I won’t tow on a new truck until it has 1000 miles to break in. Getting pretty ticked off, no call from GM or the dealer from my messages yesterday.

If I get out of this, I will probably pay the price penalty and get into an F150 5.0L V8 10-speed with 3.31 or 3.55.