2020 Hyundai Sonata: jerking or lurching

Filed Oct 15, 2026 · Brakes, Engine · KY

Vehicle experienced intermittent, severe powertrain defect resulting in a critical safety hazard. Between 30K and 36K miles, the vehicle underwent 3 violent highway deceleration episodes. During these events, the engine began shaking, escalating to violent shaking; with deceleration and coming to a stop, it would shake, then sputter as if it would die. Coming to a complete stop, a total stall was prevented only by the ECM forcing a limp mode lock at 1200 RPMs. When Auto Hold was engaged at this point and my foot was removed from the brake pedal, the mechanical surge caused the vehicle to unexpectedly lurch forward, fighting against and nearly overriding the factory Auto Hold braking safety feature before finally holding. Luckily, no pedestrian was walking in front of my car when this occurred. No check engine light (CEL) or dashboard warning ever illuminated. This safety compromise is directly tied to an ineffective or adjacent remedy involving Service Campaign 9B1 (Opcode 40D219R0) and Safety Recall 286. Under this Opcode, a factory software flash deleted the standard OBD-II trouble code P0451and substituted it with a manufacturer-specific shadow code P14EE00. This software manipulation suppressed universal emission/pressure sensor faults, masking a volatile physical defect within the high pressure fuel delivery and ignition systems. Dealer diagnostics on a running, compromised engine flagged an improper fuel injector pulse and subsequently a failing Cylinder 3 ignition coil. All four injectors were replaced but only one coil, leaving 3 non-updated , factory defective coils in the engine. The vehicle remains an ongoing highway stalling and brake-override hazard due to an incomplete field remedy of a recall-adjacent system. I've filed a Hyundai Complaint with assigned case number 43394228 regarding Safety Recall 286. (Two episodes of the attempted Auto Hold override occurred - first 09/09/2026 and second 09/29/2026.)

Filed Jul 10, 2026 · Electrical, Engine · AZ

My vehicle while driving, it is jerking and shaking. When I come to a stop, the cars rpms go up and down while the car is shaking. When I pressed the gas pedal to accelerate the car will not accelerate as normal and the car jerks as I’m driving it. The RPMs rev up and down without any pressure placed on the gas pedal. The check engine light came on.The miles per hour only allows me to put one digit. I wanted to clarify that the problem is occurring anywhere between 0 mph to 65 mph when these the car jerks and shakes and the RPMs go up and down without me pressure on the gas pedal.

Filed Aug 19, 2024 · Fuel system, Seats · TN

Took a trip to Nashville so I left Memphis Saturday morning hole on the road heading to Nashville I was at least 30 minutes fork the city my car began to jerk very bad suddenly my file light came on so I stopped at a gas station the file light came on telling me I needed gas the had was on the E but my mileage to e said 117miles. So I was like ok that’s weird after I put gas in my car I got back on the road my gas hand went from full to half way and I was not even on the road for 40 minutes so as we get closer to Nashville my car starts jerking very bad I hear a noise that sounded like a bag or a piece of paper being crumbled up I turn around to find my rear seat up in the air I knew it was not normal at all looks like it was a lot of pressure for the frame of a car to stand up like that I definitely knew something was wrong when that happened I instantly started to smell gas very loud smell of gas I then start to do my research and I see Kia’s and Hyundais are dealing with gas tank expansions so at this point I am scared for my life I’m in my car and I’m dealing with a issue like this. I instantly call my dealership and schedule to have my car towed to the dealership out in Nashville. They called me that Monday confirming the gas take had expanded and caused a significant amount of floor damage to my vehicle I am currently waiting trying to see what is Hyundai going to do about this issue that is my only transportation and having to deal with this then find another way back home has been very stressful and just to know that I could have lost my life in that car is even more traumatic

Filed Jul 25, 2022 · Driver assistance, Electrical · TX

I first begin having an issue with the idle speed. It would jump up to 1,500 RPM, which is twice the normal 750 RPM level It started almost from the very beginning when I purchased this car new in early 2020. I mentioned it at first oil change at dealer at 3,500 miles. I was told it was normal. In the beginning it would come and go. Sometimes not happening for weeks in-between episodes. Then it started to have the check engine light come on after it would happen and stay on. I took it back while light was still on and they kept the car for several days. Said it was the EPV valve and replaced it. Car operated fine for a few days then started up again. It also started to idle up and down from 1500 down to 500 in a rapid succession. I was able to get it to stop sometimes by turning engine off and them back on. Again I contacted dealership and took car back in. They gave me a loaner car and kept my car for over a month. This time they replaced the computer they told me. I did not have car for more than a week before it started doing it again. It has gradually gotten worse and happens more often now. It has also started to have the Forward Collision Avoidance warning come on in addition to check engine light as well. Just this week it actually just died on me while driving and forced me to pull to side of road. Turn off the engine and restart the engine. This happen 3 times in succession. Dealership does not seem to have any idea on what is going on and have been not very helpful. 3 week wait to get an appointment to bring in and no loaner cars available. This problem with the 2020 vehicle is very dangerous. It can idle up at anytime and car will lurch, requiring forceful brakeing . Car dying while driving and losing power as well.

Filed Jul 19, 2021 · Driver assistance · MT

The driver seat belt pops out sometimes for reasons unknown. The speakers suddenly stop working at random times so I got lost while listening for navigation directions safely paying attention to the road instead of watching the screen for upcoming turns. And the biggest one, a few times I almost crashed into oncoming cars and guard rails because if the road has a dip the sonata decides to jerk hard to the side and overcorrect itself when lane assist is on. When the road is level it just beeps annoyingly loudly when it can't see the lines or you accidentally cross over it, but does not actively assist even tho active lane assist is on. This is a major safety issue!!!!!

Filed Jun 20, 2021 · Transmission · TX

The transmission since we got the vehicle has had random hard shifts. The software updates seemed to have alleviate some of the occurrences. How ever when it does happen now. The whole car shakes while at idle and shifts extremely hard. Almost like braking hard. The problem has not been reproduced at a dealership yet, taking it in ASAP for inspection. Noting relating to the power train has been replaced. Just a software update a while back. No warning lights came on the screen when it happened. My wife was going about 20 miles per hour when she tried to accelerate. It was hesitant than shifted hard, lurching forward than accelerated. When she came to a stop at the next light it was shaking the whole car.

Filed Jan 4, 2021 · Transmission · 2,000 miles · IN

Occasionally there is a serious delay when trying to accelerate. Car tends to jerk/buck when accelerating, usually in the lower gears. I have no idea if this is a transmission issue or a fuel injection issue, but my dealership has not been able to detect an issue and keeps telling me everything is normal when it clearly isn't. The car also has harsh downshifts especially going from 2nd to 1st gear.

Filed Nov 27, 2020 · Fuel system · 1,600 miles · MA

As the vehicle was at a complete stop and waiting for a chance to get in traffic, the car hestiated and would not respond to the depress of the gas pedal, for a second or two... Very strange indeed!....is it a transmission issue or something else....the transmission shifts strange from the complete stop position...this happenes more than once! And one instance it actually jerked ( bucked) somehow...concerned about this...