This is a very simple problem with a very simple solution, but Penske Hyundai, the dealer where I bought this 2017 Sonata, refuses to acknowledge it. Hyundai intentionally programmed the computer that shifts the transmission so that when it's in the eco mode or the normal mode the down shifting is delayed until the engine lugs and shudders. I suspect they did this to keep the engine RPM low and help save fuel. I know this is the case because the problem goes away if you drive it in sport mode. When I took it in to Penske , they claimed they couldn't duplicate the problem. However, it was in eco mode when I dropped it off, but it was in sport mode when I picked it up, suggesting that they zeroed in on the symptom. I know they can alter the shift points on the transmission and solve this but the gas mileage would be reduced and they could get into problems with the EPA. It's embarrassing to have a brand new car and your passenger asking you what's wrong with the engine? I am planning to take it in two more times and then take it to Aamco for an expert confirming opinion; and then assert a California Lemon Law claim. Maybe that will get Penske Hyundai's attention!
Update from Feb 2, 2018: I just had a long conversation with the Penske Hyundai service manager. She drives a Hyundai and has experienced the same shuddering and lugging and agrees it is caused by a delayed down shift, especially in the eco mode. Her solution? She doesn't drive the car in eco. How simple! Why didn't I think of that? She went on to say that the shuddering and lugging in eco and to a lesser extent in normal mode is "normal." Furthermore, the shift points can't be changed to remedy this because it would affect the EPA mileage rating. (Remember what happened to VW and their diesel that was software-rigged to pass smog tests? Hyundai doesn't want to go there!) So there you have it.. Hyundai intentionally set the eco and normal mode shift points to delay down shifting, thereby keeping the engine RPM low and saving a little fuel. Never mind the irritating vibration and the reduced oil pressure under lugging load, which will shorten engine life.
This is a very simple problem with a very simple solution, but Penske Hyundai, the dealer where I bought this 2017 Sonata, refuses to acknowledge it. Hyundai intentionally programmed the computer that shifts the transmission so that when it's in the eco mode or the normal mode the down shifting is delayed until the engine lugs and shudders. I suspect they did this to keep the engine RPM low and help save fuel. I know this is the case because the problem goes away if you drive it in sport mode. When I took it in to Penske , they claimed they couldn't duplicate the problem. However, it was in eco mode when I dropped it off, but it was in sport mode when I picked it up, suggesting that they zeroed in on the symptom. I know they can alter the shift points on the transmission and solve this but the gas mileage would be reduced and they could get into problems with the EPA. It's embarrassing to have a brand new car and your passenger asking you what's wrong with the engine? I am planning to take it in two more times and then take it to Aamco for an expert confirming opinion; and then assert a California Lemon Law claim. Maybe that will get Penske Hyundai's attention!
Update from Feb 2, 2018: I just had a long conversation with the Penske Hyundai service manager. She drives a Hyundai and has experienced the same shuddering and lugging and agrees it is caused by a delayed down shift, especially in the eco mode. Her solution? She doesn't drive the car in eco. How simple! Why didn't I think of that? She went on to say that the shuddering and lugging in eco and to a lesser extent in normal mode is "normal." Furthermore, the shift points can't be changed to remedy this because it would affect the EPA mileage rating. (Remember what happened to VW and their diesel that was software-rigged to pass smog tests? Hyundai doesn't want to go there!) So there you have it.. Hyundai intentionally set the eco and normal mode shift points to delay down shifting, thereby keeping the engine RPM low and saving a little fuel. Never mind the irritating vibration and the reduced oil pressure under lugging load, which will shorten engine life.
- Stan Z., San Diego, US