2021 Kia Seltos: shudder or vibration when accelerating

Filed Sep 4, 2026 · Engine, Transmission · TX

Car began throwing a P0304 code in June of 2025. I took it to Brookshire Car Care and they ran a diagnostic, but found nothing to be wrong. In November of 2025, the car began throwing a P0304 code again and this time also had a P0303 code and P0335. The car was taken to Christian Brothers as it was unsafe to drive and the closest mechanic to my location. They found the crankshaft sensor to be damaged due to metallic debris. In March of 2026, the P0304 code came on again and I now took it to the closest Kia dealership. They determined 2 coils and all spark plugs should be replaced. Now, again, the P0304 code is back as of [XXX]. I have a long list of symptoms that include the metallic debris on the crankshaft sensor, rapid oil loss, frequent rough starts on a cold engine, a metal ticking sound, constant idle vibration, a/c shuddering when car is idle or turned on and in park. The dealership has said they will not acknowledge the findings of Christian Brothers because they are not the ones who made the repair. They said they will do a thorough test on my engine, however they continued to insist it is likely a fuel injector issue. I am concerned there is extensive engine damage and they are going to try to get out of the repair by saying it’s a cheaper fix and not determining the actual cause. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Feb 26, 2026 · Engine · 72,000 miles · NH

The contact owns a 2021 Kia Seltos. The contact stated that while driving 65 MPH up a slight hill, the vehicle shuddered significantly and failed to accelerate upon depression of the accelerator pedal. The check engine warning light then started flashing. The driver was able to pull over to the side of the road. The vehicle was taken to Hamlin Automotive on several occasions. The mechanic replaced 4 spark plugs, oil piston rings, and the camshaft; however, the failure persisted. The mechanic advised the contact that the failure might be related to the fuel injectors. Additionally, the mechanic had informed the contact that the vehicle might be experiencing excessive oil consumption. The contact received notification of the federal safety agency Campaign Number: 25V099000 (Engine and Engine Cooling), and the vehicle was taken to the dealer for recall repair; however, the contact was informed that no issue was found upon inspection of the vehicle. The contact stated that while driving at 65 MPH, the check engine warning light started flashing. The driver pulled over to the side of the road. The vehicle was towed to the independent mechanic, where it was diagnosed and determined that the engine had failed and needed to be replaced. The vehicle was not yet repaired due to the cost. The contact related the failure to the recall. The manufacturer was contacted and referred the contact to the dealer for assistance. The failure mileage was approximately 72,000.

Filed Feb 24, 2026 · Acceleration, Transmission · PA

Shuddered into limp mode at a stop sign. Has a sever shudder that throws it into limp mode, loses ability to drive in reverse and then loses ability to drive at all. Has issues shifting gears while driving causing the engine to rev itself while driving. Vehicle has left me stranded on multiple occasions. Has nearly 75,000 miles and I've put just over 4,000 of those on it since acquiring it at the end of October/Beginning of November.

Filed May 13, 2024 · Engine · 16,927 miles · PR

The contact owns a 2021 Kia Seltos. The contact stated that after starting the vehicle, the vehicle started shuddering. No warning lights were illuminated. The vehicle was taken to an independent mechanic where it was diagnosed with needing to replace a piston ring in a cylinder. The vehicle was not repaired. The vehicle was taken to the dealer to be diagnosed, and the contact was told the engine needed to be repaired. The contact related the failure to the federal safety agency Campaign Number: 21V259000 (Engine). The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was 16,927.

Filed Aug 30, 2023 · Fuel system · CA

I've owned this car since it was new. I've been disappointed with the transmission. At low speeds, it will hesitate and shudder. This is especially true if I'm making a turn. This has been a consistent problem. Secondly, twice my transmission has overheated. The first time we were in a Halloween event during the Pandemic 2020. It was a drive-through event that was stop-and-go. The warning light came on with the gauge showing one bar over the limit. As luck would have it, the traffic started to move towards the end and it lowered the bar to just under the overheating bar. The second time this happened it was much more serious. I had four people in the car. We had just left a restaurant and were heading towards the freeway. Unfortunately, we got stuck on a hill in Hollywood Bowl traffic. We were stuck there long enough that my car shut down on the hill. We were blocking traffic and my wife got out to direct traffic around us. I tried to put the car in neutral and coast towards an open curbside parking space. It wouldn't budge. We spent what felt like an eternity blocking traffic. It was probably 4-5 minutes where we were unable to start or roll backward.

Filed Dec 2, 2021 · Transmission · NH

Brand new car on Dec 2020. Second time with a transmission problem. Was repaired at 6500 miles in June of this year. Dealer replaced it with a re-manufactured one. At 9300 miles I was driving in cruise control at about 70 miles per hour for a couple hours and while going up a long hill the transmission started slipping again and rpms went from 2000 to 4000 while it was trying to shift. The car began to shudder just like back it june so I knew the transmission was going. I slowed down and pulled off highway as the transmission continued to slip and had no power to go above 20 mph. I saw a parking lot up the hill to pull over at to be more safe off the highway and the rpms went up to 6000 and barely moved car then it caught and lurched the car forward and I almost hit the sign in the parking lot. I waited over 3 hours for a tow truck and after car cooled it did move enough to get it near the tow truck to be pulled up on the flatbed. This car needs a beefier transmission or some kind of cooler or warning light to prevent accidents. When is it a lemon and due for recall??

Filed Jun 25, 2021 · Transmission · NH

Driving on a busy 4 lane highway where everyone was going over 70mph. Car began to shudder in the transmission and lost most of its power. Rpms went up to 3 or 4 thousand when stepping on gas to pull out out fast traffic and wouldn't go above 35 mph. Had to slowly pull out of traffic with hazards on at 30mph with cars flying by in both sides. Finally got to breakdown lane after a mile and tried to use sport shift mode to try other gears. Car wouldn't go above 30 mph and rpms went up to 4000. Luckily there was a rest area 500 feet off the highway. Pulled in there to look at transmission oil dipstick but couldn't find it. Spent over 2 hours trying to get Kia roadside assistance towed to a LOCAL Kia dealer but none had loaners to give so had to use my AAA to tow it to my dealer where I bought it. Hopefully I will get reimbursed for the tow I had to pay for. Still waiting for my service department to fix it. They tried to drive it and confirmed the transmission is gone. The car ONLY has 6500 MILES ON IT!!!!!! No warning light came on to know problems were present. Very dangerous.... Kia needs to have a transmission oil cooler or a warning light installed so this can't happen again!!!!