2020 Kia Optima: shudder or vibration when accelerating

Filed Mar 11, 2026 · NE

It either has issues shifting gears like its stuck or the transmission may be slipping, it's had this issue since I bought the car. However I wasn't aware until my uncle drove the car and said something might be wrong.. I have no idea what's causing it. It shudders when I make turn or speed up to pass. Not all of the time but at least twice per my normal trip

Filed Jan 5, 2026 · Airbags, Fuel system · AZ

I purchased in July 2020, from sept 2020 I've had it at the dealership with shuddering, stalling and loss of acceleration. I originally thought fuel pump or transmission but kia said no. then in 2022 I received a letter from kia corporate stating low pressure fuel pump failure. so i called the dealership and told them the letter states everything I had been in to see them about numerous times. made an appointment they said they found an error but had no fix. I complained heavily due to the fact I sat there for 4 hours, and they knew they had no fix as of yet. It was too dangerous like this. so the Manager said he'd just replace it with a whole new fuel pump but it could also fail. I sent the car in for 4 days just to find out they did not replace it. they only changed the fuel filter. stating kia wont let them put in a new pump due to their system not showing any other issue. The problem persisted and multiple visits to kia to no avail. Then on top of that my air bag light came on Jan 4, 2024. They said it was my responsibility it's not covered 1138.67 it would cost me. Then in Feb kia corporate sent me a letter about airbags. I did not go back because the light eventually went off by itself without a fix, then April 17, 2024 the original problem got even worse, shuddering, lack of acceleration , stalling feeling. Dec. 10, 2025 back to Kia. they have a code for dual clutch and flywheel so they ordered it & had my car for 19 days. I called numerous times to see about progress. I was told they are trying to chase down a code with a tech line. 7 days after that I picked it up & they said they did not change out any parts because there was no code. They only did a cap discharge. I have my car back now after 19 days & it's still not fixed. I called Jan5, 2026 and they said if kia is to fix it they need a code to be present or it'll cost me several thousand, even if its a known issue. so far it's been in the shop 9 times and 24 days total.

Filed Aug 27, 2025 · Transmission · NY

The vehicle experiences a dual-clutch transmission shudder in low gears and at low speeds. This issue causes a sudden loss of speed in situations such as merging onto a highway, leaving a parking spot, or while driving at approximately 30 mph. The shudder occurs randomly and poses a serious safety concern. The problem first appeared in 2020 when the vehicle had fewer than 5,000 miles on it. Beginning in 2024, at around 20,000 miles, the condition began escalating rapidly, with the shudder occurring more frequently and with greater severity. All incidents have been recorded on dash cam and provided to the dealership’s service department. The vehicle has been serviced multiple times for this issue and was kept at the dealership for approximately six weeks in total. Despite this, the dealer refuses to acknowledge the problem, citing the absence of warning lights. When the clutch was adjusted at my request, the issue temporarily improved but returned about three weeks later. The shudder now occurs more often and with greater severity, frequently forcing the driver to pull over for safety. This ongoing transmission defect creates unsafe driving conditions, and the lack of acknowledgement or permanent resolution by the dealer further increases the risk to the driver and others on the road.

Filed Jul 17, 2025 · Transmission · CA

After complaining about clutch judder resulting in getting anti-judder logic software update, followed a month later by transmission serviced, transmission suddenly failed while driving in heavy traffic on the freeway. After repairs, judder keeps happening at low speeds on the freeway or slow speeds under load.

Filed Feb 3, 2025 · Transmission · AZ

At gas, the vehicle jumps/judders as if it’s not getting enough gas to get up and go, and then at higher speeds it goes fine. Was reported to Horne Kia while under warranty. They never found the issues. Months later issue was found by a new mechanic, now the vehicle is no longer under warranty and the TRA codes are posted online. [XXX] Reported August 2021 [XXX] Reported December 2020 INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Oct 2, 2023 · Engine · 123,000 miles · OH

The contact owns a 2020 Kia Optima. The contact stated that while her husband was driving at an undisclosed speed, the vehicle was shuddering. The contact's husband was able to drive to the residence. The vehicle was then towed to the dealer, where it was diagnosed with DTC Code: P0304 “Cylinder # 4 misfire). The contact was informed that the engine needed to be replaced. The dealer informed the contact that the warranty had expired. The vehicle was not repaired. The manufacturer was made aware of the failure and advised the contact to file a complaint with the federal safety agency Hotline. The failure mileage was approximately 123,000.