2018 Kia Optima: sudden loss of power

Filed Mar 11, 2026 · Body, Engine · GA

My teenage daughter regularly drives this vehicle. The vehicle began experiencing significant oil consumption, oil leaks, and intermittent loss of power. During an early inspection at an independent repair facility, a check engine code P1326 was identified. Due to the symptoms and diagnostic code, the repair facility advised that the vehicle could be heading toward engine failure and recommended that the vehicle be taken to an authorized dealership because potential engine issues may fall under manufacturer warranty coverage. The vehicle was then towed to an authorized dealership. During the first visit, the dealership retained the vehicle for an extended period of time, approximately two months. During that visit, several recommended services were completed, including replacement of spark plugs, ignition wires, and replacement of the valve cover gasket along with other recommended maintenance. During that visit, it was also stated that the vehicle has a known issue with excessive oil consumption. Because of this, the oil level is checked weekly and oil is added as needed. I also informed the dealership that the independent repair facility had identified code P1326, but I was told that the dealership diagnostic codes were different. After these repairs, the vehicle experienced another incident where it lost power and began idling roughly while being driven on a busy highway. The vehicle was taken back to the dealership. During that visit, it was stated that the fuel injector harness and oil pressure sensor needed to be replaced. The dealership also indicated that the spark plugs needed to be replaced again, even though they had been replaced at the same dealership less than a year earlier. At that time, I asked if the vehicle would be safe to drive for approximately one week because I needed to travel out of town and my daughter would need the vehicle. The dealership advised that it was safe to drive during that time. The vehicle was then brought back to the deal

Filed Dec 10, 2025 · Engine · NM

While driving my 2018 Kia Optima S, the car suddenly jerked, lost power, and stalled in traffic. Multiple warning lights came on at the same time including the oil light, battery light, and check engine light. I had no acceleration and the brakes became very hard to press. The vehicle had to be towed for safety reasons. The Kia dealership inspected the vehicle and confirmed internal engine failure due to “cylinder failure” and stated the engine needs complete replacement. This failure occurred without any external leaks and without warning other than the sudden loss of power. The dealer stated the issue is not covered, even though it is clearly an internal engine malfunction. This is a major safety hazard because the stall happened while I was in active traffic. A sudden loss of power and braking ability puts me and others at risk of an accident. The problem has been confirmed by the Kia dealership through diagnostic testing. The vehicle is still available for inspection. Warning lamps appeared only at the moment of failure, giving no advance warning. This appears to be related to the ongoing engine defects in Kia vehicles involving oil starvation, loss of compression, cylinder scoring, and internal engine failure. Cylinder failure and sudden stalling should be investigated as part of the known safety-related engine defects affecting this model.

Filed Aug 3, 2025 · Engine · CA

My 2018 Kia Optima went into limp mode while exiting the freeway. I had it scanned and received a P1326 code, which is directly tied to the known engine knock sensor / bearing wear issue in Kia models. The engine light came on and the car lost power suddenly. This created a very unsafe situation. I contacted Kia, and they confirmed that my VIN is not included in the engine recall (KSDS campaign), even though my symptoms exactly match the covered vehicles. I am now stuck with an undriveable car and no recall coverage, even though I’m facing the same failure risk. I believe this VIN should be included, and that this is a clear safety issue. I am requesting the federal safety agency to investigate and push Kia to expand coverage to include more affected vehicles.

Filed Jul 3, 2025 · Engine · OH

The 2.4L Theta II engine in my 2018 Kia Optima is failing, exhibiting excessive oil consumption, with oil loss documented at over 1 quart per 1,000 miles, leading to secondary failures in the catalytic converter, clogged with oil carbon and breaking into pieces that may damage the cylinder walls, and the spark plugs, which are fouled with carbon, causing misfires. The engine and related components remain intact and un-repaired, pending Kia’s required 3,000-mile consumption test. Safety of drivers have been put at significant risk. The excessive oil consumption and potential engine seizure threaten sudden loss of power, especially on freeways where car fails to accelerate to city and highway speeds, increasing the chance of a collision. The clogged catalytic converter poses a fire hazard, (reported by the federal safety agency investigations into Theta II) where oil leaks or debris can ignite on hot surfaces. Risk is heightened during the mandated 3,000-mile test as well. Problem has been confirmed by both a dealer and an independent service center as recent at 1 July, '25, documenting oil loss and new engine recommendation. Symptoms began with noticeable oil loss during oil changes, starting at least 1 quart per interval on May 10, 2023 (mileage 43,374), with the loss increasing over time. Misfires and RPM loss during acceleration first appeared after the oil valve gasket replacement in late May 2025, and freeway pickup issues became apparent around mid-June 2025. The full engine failure was confirmed by Spitzer on July 01, 2025.

Filed Jan 20, 2025 · Acceleration, Engine · MS

My engine burns oil very bad. Black smoke comes out of my tailpipe and I burn through 5 quarts in less than a thousand miles. I just got my oil changed two weeks again and I just had to add more oil to my car bc it was empty. I’ve had to replace the spark plugs twice due to soot build up. I can’t afford a new car I’m 17 and can barely afford the maintenance let alone a whole new engine. Have spoken to many mechanics and they all say the same thing “it’s a Kia it’s gonna burn oil” ITS A KNOWN ISSUE. And yet Kia will not resolve it bc they don’t want to spend their own money to fix their mistake. I got an estimate for a new engine which is basically crucial and it’s over three grand. No matter where I take it everyone always says the same thing- to get rid of it before it’s too late. But I simply cannot afford to do that and I know my car is not the only one with this issue so many other people with the same car/engine have the same issue. 2.4 L GDI !!!!! I wish someone would have warned me before buying Kia. A recall to fix this issue is needed now. I lose control of the speed sometimes. I will keep my foot at a set position on the throttle and the engine will take off because it’s jumping to the usual power it should have. ( it has reduced power most of the time bc of the struggling engine) sometimes on the highway I’ll get a sudden burst of power and I have to let off the accelerator. Not safe at all

Filed Oct 2, 2023 · Acceleration · CO

What component or system failed or malfunctioned, and is it available for inspection upon request? ******Speed Control- Vehicle will stall while on road/ highway causing rear vehicles to brake. How was your safety or the safety of others put at risk? *****Several times I was forced to pull over to side lanes to avoid being rear ended. *****Has the problem been reproduced or confirmed by a dealer or independent service center? I have called dealership several times in regards to this issue, all I was told was to do not use A/C or heater as that will make the vehicle lose power. Refused to conduct was full inspection of vehicle. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? *****No, no it has not been inspected Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? *****No warning lamps not symptoms of the problem prior to the failure.

Filed Aug 8, 2023 · Engine, Fuel system · TX

I'm reporting these issue pertaining to the engine within the first 3 weeks AFTER the engine replacement recall was serviced and completed. The vehicle was exhibiting the same defects and major health and safety hazards as before the new engine. Intermittent engine failure, even worse, while i was trying entering the hwy at speeds of 45-50 miles it jerked very violently and loss total power while vehicles were behind me nearly rear ended. Prior to this I reached out multiple times to have it serviced at again. The original service department didn't respond, so I called other service departments and was told it needed to be serviced by the original dealership/service department that replaced the engine. I had the vehicle in normal working conditions a few days before it began exhibiting the same problems as before the engine replacement. It was in operable condition but still stalling and refusing to crank unless primed, until it ultimately just would not crank at all and is back in the same condition it was before the new engine but it is not locked up currently. The time frame and Milage between first experiencing the issues to now, March 2023-64745 Started shuddering, loss of power while driving, but would crank right back up without issues. Happened a few times, charged up battery thinking is was am electrical issue. April 2023 More frequently the issues occurred, still same severity levels. May 2023 Began happening every time at an idle, whether I was at a fast food in drive through placing an order, or to wash the car. Every time at an idle this would happen, and would take a few times of trying to start the vehicle and after about 5 seconds of cranking it would catch and work. I began placing the vehicle in neutral while at idle and it would assist In the stalling out sometimes. After a few days of this it refused to crank due to the engine locking up. Milage at this time was 68048. Aug 2023-New engine, drove about 2k miles-70207 current

Filed Jun 6, 2023 · Engine, Fuel system · 68,000 miles · TX

High injector fuel pump top engine mount went out at 68000 miles. It caused the vehicle to stall and lose power and basically cut the car off while driving.

Filed Apr 27, 2023 · Engine · MO

My car engine burns oil EXCESSIVELY. After an oil change, 2 weeks later i had to put more oil in. The dealership is no help even with a warranty. The car burning oil is also causing other mechanical problems that are a hefty price that are only a temp fix. I have to put oil in every single week. 2-3 quarts a week. Due to the oil being burnt off, it has affected my spark plugs and has caused a misfire in the same exact cylinder for when it misfired for this same problem, a year prior. I took it to a kia dealership last year and they performed a combustion chamber cleaning ($650+) and it only worked for 3 months before my car was back to performing poorly due to power loss from misfiring again. This car has put me in a VERY TOUGH financial situation and the dealership and corporate are absolutely no help. a year apart, this car has misfired on the same cylinder twice. the dealership just tells me to do a combustion cleaning but due to it being very pricy and with how much oil i have to buy, it’s not an option for me due to my financial situation. right now i’m just hoping something will be done for the millions of people that are effected by this.

Filed Aug 1, 2022 · Engine · GA

First incident occured when I was driving to work. The engine made a noise and loss power which almost resulted in a crash. I contacted kia, they explain to me that a knock sensor need to be installed and software needed to be updated. They installed it and return the car to me. Now again while I am on the highway I hear a loud knock, lights flashing in the car and the car has loss power. I rolled off the exit pull over and called a tow truck. While waiting I check the oil in the car thinking maybe the engine is locking up. There is no oil in the car, which is strange because two months prior kia just did an oil change. I have documents to prove everything. Kia has been the only dealership that service the car. They now been in possession of my vehicle for four months now and nothing has been done. I contacted cooperate and they have failed to getting back to me after numerous attempts to get answers. Please someone help me. I have congestive heart faliure which I explain to them and I really need my car but most of all I need it to be safe for me.