[Algeron]

This has been an issue for some time. However, I finally found some more details. Has anyone else experienced this?

I have a 2016 2ss with the A8. I have had the shudder issue in the past, and that led to a torque converter replacement. Also, the TCM has been replaced twice. However, I have had an ongoing issue that I can never duplicate on demand. There are times when I floor it that the car will hit about 4k RPM, then cut all power like it is in neutral. When the RPMs drop to about 2k, it will go back to normal behavior. If I stay easy on the throttle, it will act normal. If I floor it again, this will repeat. I noticed this over the weekend when I passed a car on a 2 lane road. I kept the throttle floored when it cut out and it regained power for about 2 seconds and dropped again. I did notice on the dash that it said 'Performance Shift Active' when it cut out (I know what PSA does, this was just the first time I saw that when the car was acting up). I came up on the next car to pass, and the behavior repeated. I changed the car from Sport to Touring, and there was no issues passing the 3rd car. I changed it back to Sport, and it repeated again passing the 4th car. However, when I drove back home that evening, it stayed in Sport and there were no issues.

I have had the car to the dealer multiple times for this, and they have never been able to find anything, or duplicate the behavior. I am considering trading for a 2021 or 2022 A10 in hopes this does not happen on the newer models (before it is said, I would love an M6, but where I live, it is not practical. 7 mile drive to work takes 30 minutes.)

My question is has anyone else had this happen? If so, any advice on what I can tell the dealer for getting this fixed? I have almost been in 2 wrecks due to this behavior. Once getting on to I95 from an on ramp, and the second was this weekend when the car behind me tried to follow me passing the second car.

I posted this in a Camaro 6 FB group as well. I did search the forums, and I only found some issues with Performance Shift, but nothing similar (unless I was using wrong search terms).

[Heat Magnet]

This may sound crazy, but try driving the car in manual mode to see if that's more comfortable. At the very least, you can control your shifts if you want to rev it up to 4,000 RPM. You probably won't get any relief with the new A10 transmission since that still has Performance Shift (which according to some here, it can activate on hard cornering).

[Algeron]

Originally Posted by Heat Magnet

This may sound crazy, but try driving the car in manual mode to see if that's more comfortable. At the very least, you can control your shifts if you want to rev it up to 4,000 RPM. You probably won't get any relief with the new A10 transmission since that still has Performance Shift (which according to some here, it can activate on hard cornering).

I can try that, but I have rarely used manual mode. Just for clarification, I am not revving the car to 4k. As for this weekend, I was running 50mph. I pulled out to pass another car, stomped the pedal, and when the car hit 4k RPM while accelerating, it cut out. I kept my foot on the gas. There was no response from the engine or transmission. Once the car coasted to 2k RPM, the car started to respond again.

[Mark114]

It sounds similar to what happens when the engine hits redline. Maybe this is an engine problem rather than a transmission problem due to a bad sensor or wire harness? Does this happen when you accelerate from a stop to highway speed?

[arpad_m]

As you probably know, this is absolutely not normal, performance shift mode should just work without the power being cut or anything similar. I use it all the time and it's an absolute boon to have, manual shifting with the paddles or even the shift lever is not too useful.

I'm far from being a transmission expert, but since the behavior is tied to very specific rpm thresholds, I bet it's a transmission programming issue (4k rpm is the rev limit for P and N, 2k rpm is the low threshold for disengaging performance shift mode). If the car is tuned already or if you're out of powertrain warranty anyway, I would reach out to a competent tuner instead of a dealership.

Also, if you try to trade the car with this known fault that is a serious safety issue, who in their right mind will buy it from you, whether dealership or private party?

[Algeron]

Originally Posted by Mark114

It sounds similar to what happens when the engine hits redline. Maybe this is an engine problem rather than a transmission problem due to a bad sensor or wire harness? Does this happen when you accelerate from a stop to highway speed?

I have not been able to force it from a dead stop. It is normally when I am running 25-50 then floor it.

[Algeron]

Originally Posted by arpad_m

As you probably know, this is absolutely not normal, performance shift mode should just work without the power being cut or anything similar. I use it all the time and it's an absolute boon to have, manual shifting with the paddles or even the shift lever is not too useful.

I'm far from being a transmission expert, but since the behavior is tied to very specific rpm thresholds, I bet it's a transmission programming issue (4k rpm is the rev limit for P and N, 2k rpm is the low threshold for disengaging performance shift mode). If the car is tuned already or if you're out of powertrain warranty anyway, I would reach out to a competent tuner instead of a dealership.

Also, if you try to trade the car with this known fault that is a serious safety issue, who in their right mind will buy it from you, whether dealership or private party?

This is why I would not be selling the car to a private party. If it is traded, it will be traded to the dealership that this issue has been reported to repeatedly. Thus, they should have full history on the car and should know what needs to be done after a trade.

As for the car, it has a CAI, but no other engine mods have been done. Partly because of this issue. It has been ongoing since I bought the car, but since it cannot be repeated on demand, it has not been an easy thing to fix. The car can go for months and never have an issue, then it will. In this case, it was a constant problem on my drive to visit family (2.5 hours away), but never happened on the way home. The last time it did this was in November of 2020. Needless to say, this is my daily, and my driving style is consistent.

I am aware of 4k being the neutral rev limit, and I have mentioned that to the dealer in the past when this has happened. The car is a 2016 with 51,500 miles and still under extended warranty. I do have a history with this dealer, so having it covered is should not be an issue.

As I mentioned, normally 4k is where it will cut out when it has done this in the past. This is the first time I have noticed the Performance Shift message when it went out. However, when I put in in Touring, the car ran as expected. Putting it back in to Sport, it cut out again. I do think it is some programming issue, but IDK where that would fall. However, I do prefer to keep the car in Sport normally.

[KingLT1]

Try putting the car in "Competitive" mode by double tapping the TCS button while in Sport mode. It sounds to me like TCS/Stabilitrak is intervening when you kick it down.

[SwordfishII]

I think King is right... You floor it, transmission shifts, car breaks traction, engine cuts power. That's the computers at work.

[arpad_m]

Originally Posted by SwordfishII

I think King is right... You floor it, transmission shifts, car breaks traction, engine cuts power. That's the computers at work.

...but always exactly at 4k rpm?

[SwordfishII]

Originally Posted by arpad_m

...but always exactly at 4k rpm?

Yeah, I'm not sure about that part.... I've experienced pretty much exactly what Algeron describes, however, I know my scenario was due to the TC intervening.



Which is the trigger? Can it be confirmed that it's happening only when approaching a specific rpm range or is the issue more related to quick and hard acceleration (like the OP said stomping the pedal)?


I'd put it in manual and see how it behaves letting the revs climb higher than the auto would let it but at slower more gradual paces.

[cellsafemode]

have you tried seeing if it's the throttle (your pedal) switch that's bad?

double tapping full throttle engages performance shift and it sounds like seeing "perf shift" was just a side-effect of the throttle switch cutting out simulating that action.

maybe see about junkyarding a new go-fast pedal and swapping it in to see if the behavior remains.

[Algeron]

Originally Posted by SwordfishII

I think King is right... You floor it, transmission shifts, car breaks traction, engine cuts power. That's the computers at work.

From playing today, I was running 70 on a fairly empty stretch of interstate. Floored it (first time from this fast), hit 5k and stopped (around 80mph). RPMs dropped to 2.5k, Performance Shift Active message appeared on dash, then power came back. There was not any noticeable wheel spin.

[Algeron]

Originally Posted by SwordfishII

Yeah, I'm not sure about that part.... I've experienced pretty much exactly what Algeron describes, however, I know my scenario was due to the TC intervening.



Which is the trigger? Can it be confirmed that it's happening only when approaching a specific rpm range or is the issue more related to quick and hard acceleration (like the OP said stomping the pedal)?


I'd put it in manual and see how it behaves letting the revs climb higher than the auto would let it but at slower more gradual paces.

Originally Posted by cellsafemode

have you tried seeing if it's the throttle (your pedal) switch that's bad?

double tapping full throttle engages performance shift and it sounds like seeing "perf shift" was just a side-effect of the throttle switch cutting out simulating that action.

maybe see about junkyarding a new go-fast pedal and swapping it in to see if the behavior remains.

As I mentioned from Sunday's experience, it only happens in Sport Mode. When I put the car in Touring (after 3 drops), did the exact same 50mph then floor, there was no issue. Put in back in Sport, did 50mph then floor it happened again.

While I have no clue at this point, it appears that it is related to Sport mode and Performance Shift mode.