Just bought a beautiful red 2016 Stingray Z51 LT3 automatic transmission. Awesome car. Only 16K miles and pristine inside and out. However, about 3 weeks after I bought it I noticed it was starting to sputter. In fact, it has gotten worse. Seems to happen mostly between 1500 and 2000 RPMs, but is not simply a gear changing thing - which is what I have read from some other posts on the Internet. I could be doing 15 MPH or 70, makes no difference. Even seems to happen when I am coasting without accelerating. It's hard to explain what it feels like, but it's like the car is jerking, or sputtering. Sometimes it is a single jerk or two, other times it is like 20 fast ones in a row. Almost like if it were driving over small bumps in the road, but it's not related to that. This happens on smooth pavement or a beat up highway. I'm not a mechanic, so I don't have any clue about some of these posts where people are speaking in that lingo. I wanted to see if any C7 experts out there have any clue what this could be so I can speak half way intelligently with a mechanic. The car has such low mileage, it's hard to consider it's anything major - plus after blowing my entire savings on it, I would hate to even go down that rabbit hole. I will probably take it to the dealership, but you know that can go. They can find $5000 worth of repairs on a new car on their own lot. With a car like this I don't want them seeing it and thinking of where they are going on vacation next, ya know?

Please any advice would be appreciated.

 

Hard to tell. A miss is challenging. It can be your worst nightmare or something really simple to fix. Either talk to some locals about a good local mechanic or bite the bullet and go to the dealer. We can't trouble shoot this kind of problem and hooking up test gear to the DTC is really the best way to pinpoint the issue.

I'd do the dealer, but I'm on an extended warranty and I've got that to rely on.

Elmer

 

Sounds like a severe case of the A-8 shutter...it happens when the active fuel management system tries to go from 8 cylinders to 4 and back...it may have already affected your torque converter as it sounds pretty bad to me. There are many threads on this forum that discuss this in detail. You should still be under warranty unless they changed coverage from my 2015 Z-51 with the auto -8 ...Take it back to your dealer and explain in the same fashion what you said here..they will want to hook up a portable computerized sensor to your car and drive it around for some time..then compare readings, then get it approved for an updated transmission fluid flush commonly referred to as a "triple flush"...plan on leaving it with them for a few days..if they are a legit dealer, they will honor things as all of them know if this issue and it is not just within the Corvette brand...Camaros and even trucks with the same tranny are having similar issues. My 2015 Z-51 with the same tranny was bought used with no issues until 24k miles when the famed "shutter" began. Mine was not as serious as you are describing yours as....and simply the triple flush did the trick under warranty...lots of people report that the torque converter was also in need of changing under warranty as well which is what you may need...wish you the best of luck and hope this helps!

 

Does this happen if you go to Manual mode and shift with the paddles?

 

This is good advice. Drive the car in manual mode and do NOT allow it to go into V4 mode. Just the fact that you have it in "M" eliminates the V4 function and see if this eliminates the hesitation or shudder you feel. If the problem goes away, then you've got a tranny issue and you need the flush at the dealer before you mess up the converter.

Elmer

 

Try what B-17/B-25 cc said...excellent thought...

 

My 2015 Z-51 started shuddering at around 11k miles. Only happens when tranny goes into v-4 from V-8 mode. I went out and bought a Range Unit
that plugs into the OBD port, and now it simply stays in V-8 all the time, and NO shuddering now. Its not a Torque Converter problem, its a problem with
the transition system. They have NO idea how to fix this.. The V-4 to V-8 transition system is only a gimmick anyway... On trips from Georgia to South Florida
with system engaged there was very little if any gas savings or mpg usage. Who buys a performance car to only have it kill half the horsepower for a few pennies.

 

Thanks for the info. I am scheduled for service at the dealership this week. Since this is an expensive car with all sorts of weirdness built in, I went ahead and purchased the extended warranty so I should be covered, with this and the power train warranty still valid.

I want to keep this thing in top shape since i plan to sell it and get something else in a year or so. I'm hesitant to mod anything on it that would be noticed by a potential buyer or included in notes in a CarFax report. So I will see what the local dealership service department has to say. I will pass along some of these comments though. This has been very helpful and much appreciated info.

 

Oh, and to add some info to my situation, I did test running it in manual mode, and I didn't notice any shuddering. But I live in a high traffic area, so I wasn't able to test it too much on that specific day with all of the stopping and starting. But I did notice it was either not as bad or not existent during my testing.

Again, thanks for all of the insight from everyone. Bummed that I saved for years for this car and didn't get it until I was in my 50s and when I finally pull the trigger on it, I am facing a potentially big service issue 8 weeks after I buy it. It's basically garaged now until I can get it fixed, hopefully this week. The car is gorgeous, but now I have to admit I am regretting spending the money on it and wish I had gotten the Porche or BMW Z4 instead. Oh well, it is what it is at this point, so I need to just suck it up and get it fixed :-)

 

U really don't have to bother with the extended warranty as this issue is covered by the 5 year powertrain warranty... After 5 years, your on your own.
The Range Unit was under $200 and a 2 minute install.. Car runs great, like it should now... The Range Unit leaves no trace on the cars computer
when unplugged, so GM cant say u modified something to cancel your powertrain warranty.
I have an order in for a C-8, and hope they ditch the mpg gimmicks.. This V-4 V-8 system reminds of the old CAGS 1st to 4th shift system.
That was a joke too...

 

Thanks Sonnie. I appreciate the info. I'm an IT geek, not mechanically inclined whatsoever, so I couldn't install the range unit if my life depended on it. Do you think the dealership would do it?

 

You just plug the Range into your ODBII diagnostic port under the dash.

 

There is really no install... Just take it out of the box, look under the left side dash, plug the Range Unit in... Some Blue lights will flash and your done.
The OBD port looks like a really large USB port... If your unsure where it is, go to any auto parts store.. They will plug it in for u..

 

When the C-7 is in Manual mode, the engine resides in V-8 mode only... It wont transition.
This feature is a huge problem with most late model Camaros and Trucks with this V-8 V-4 system.
Range is selling a ton of these to fix all of them.

 

Installing the Range unit is easier than changing a light bulb in a lamp, no screwing! Open box, take range out of box, hold range in hand with prong ends facing away from palm, look for similar shaped fitting hole under left side of dash, plug in. Done.


Forgot, drink congratulatory beer after massive exertion of install.

Elmer

 

HAHAHA! Love that ;-) I may go that route. Just dropped off the car at the dealership. Felt sick to my friggin' stomach as I walked away. Can only imagine what they are going to say or try to avoid doing. Just makes me sick. I love that car so much. It's amazingly beautiful, and a glorious American icon. But now I am regretting getting it instead of the German sports cars that were also on my short list. I have no issue using a Range unit temporarily, but that doesn't do me much good when I try to sell it. I'll have to yank it out before I sell and then the new buyer will test drive it and feel the epi-friggin-lectic fit it goes into and walk away - as would I had it done it at the dealership that I bought from. Sort of makes me wonder if they KNEW it had this issue and did a triple flush so it would run well during test drives. No way to know now. I'll post back the final results from the dealership for any future victims of this garbage.

Thanks all!

 

I know how u feel, especially after spending over 75 k for a car that has a built in problem when they made it years earlier, and didn't correct it then.
I test drove a C-8 and put my order in immediately.. That car felt so much more sophisticated and tight than my C-7 with only 13k miles on it.

I don't even like taking my C-7 in for ANYTHING at the dealer.. This issue is a real problem for them, yet they continued to sell them without fixing
it in 14 when the car came out..GM has lost a lot of creds with me, but hopefully the C-8 will help bring it back. My first car out of high school was a Z-28 and have
been a loyal GM Chevy guy since.. I love the way the dealers dance around this issue..!
When u decide to unload it, just sell it as is with the Range unit installed to a
dealership that buys cars without the expectation of a trade like Carvana, or Auto Nation.. They give really fair trade in value.

 

Please post what your dealers shop says your problem is, and what they are doing to fix it. I live in the mountains of north Georgia, and all
the surrounding dealers up here have no solutions. I have been cataloging all their responses to this problem and their supposed fixes to eventually
get enough to send to the local GM service rep up here...

 

I believe that I "pegged" the issue to a "t" in response number 3 to the thread...My servicing dealership is located in Gainesville, Ga. which cannot be far from your location. They made no attempt what so ever to avoid trying to fix the problem...and did just that...fixed it (so far)...and told me if the issue came back...to bring it back and they would go further with the issue even if it came to a damaged TC replacement as a consequence of the issue which would remain on record just in case it did get worse again....so far, so good with the triple flush that they did under warranty even after the tech that drove my car couldn't feel the shutter, (but the on board computer did.) (and so did I). The name of my servicing dealership is Hardy Chevrolet off of Browns Bridge Road in Gainesville,Ga. They have provided a very honorable "down home" kind of dealership experience and will remain as my service dealer and if a decide to purchase a newer Vette (C-8) I will buy it from them as well. When they tell me my Vette will be stored overnight "inside", I trust them to do so...etc etc...Hope this helps! My service adviser is Chris Wehunt...

 

The last dealer that looked at the car did the triple flush, over a 3 days period, and it did seem to help for about 1500 miles or so.
Took it back to them and said GM didn't have a service bulletin on the fix, and did the triple flush based on what other dealers were told to do, but
no official word from GM to do it. I never liked the way the engine transitioned and the bump u get when it transitions and drops to a lower gear at the same time
under hard acceleration.. The car has no other issues and enjoy driving it in V-8 only now... Even if this problem didn't occur, I would still have installed the
Range unit to eliminate the transition, and loss of power issue, not to mention the exhaust note in Sport Mode that disappears in V-4.