2016 Kia Optima: misfire or rough idle

Filed Jul 3, 2026 · TN

Code was on and off for a cylinder 2 misfire was off at this point (intermittent misfire) ecl was off car stalled out at 3rpms while driving, tiny puff of smoke once came from between the air intake and the engine, and also no crank no start but car has power. I’ve kept up with the oil changes every 3000 miles car had fluids in it and nothing looked bad all 4 spark plugs were burnt and i replaced them and still no success.

Filed Jul 2, 2026 · GA · fire

I had just stopped at stop sign and I turned right. My speed was approximately 40 mph and there was a LOUD POP. I immediately hit the brakes and had NO BRAKES. I got car off road and smoke was already coming from under hood. It caught fire immediately and burned up. Total loss . About 6 months prior to it burning I had a good bit of front end work done on it with bearing issues. Also put a new set of tires at same time . The coils and plugs were changed often because it would misfire. I purchased car July 2025. All my documents were burnt also .

Filed Jun 16, 2026 · Engine, Fuel system · CA

My 2016 Kia Optima equipped with the 2.4L DOHC I4 GDI engine began to experience progressive and severe oil consumption during the latter part of my ownership. The oil warning light began activating repeatedly, even after shortly getting the oil changed. Several certified mechanics and oil change service stations told me this was an ongoing issue with this car and engine and that there was nothing I could do but monitor it and keep it filled. At their instruction, I monitored and had it changed more frequently, often topping it off at the oil change station and at home when needed. Approximately 2 weeks after an oil change upon putting the car in reverse it started to shake uncontrollably. The car was towed to a mechanic who stated I needed an engine. I then towed it to an authorized Kia franchise dealership where the technician documented the oil consumption complaint, confirmed a Cylinder 2 misfire code, performed a borescope inspection, and found the Cylinder 2 exhaust valve burnt with a chunk missing. Engine replacement was recommended by the Kia dealership technician. Prior to my purchase, the engine had already been replaced at approximately 80,000 miles under recall-related circumstances. The replacement engine installed by a Kia dealership subsequently failed, exhibiting symptoms consistent with the documented widespread defect affecting the 2.4L DOHC I4 GDI engine in 2016 Kia Optima vehicles, including severe oil consumption, cylinder misfire, and catastrophic internal engine damage confirmed via borescope at a Kia franchise dealership. Kia America denied the claim based solely on mileage despite the damage being confirmed by their franchise technician. My vehicle became unsafe to drive due to this engine instability shortly after starting before becoming fully inoperable. My vehicle has been non-operational for approximately 5 months. Kia has not provided a substantive written determination despite a formal written demand submitted in March 2026.

Filed Jun 8, 2026 · Engine, Fuel system · TX

The car returned P1326 and had multiple misfires and audible knocking, the dealers will indeed fight the already existing class action warranties. Was sent home and told to “drive the fuck out of it”, to which the car did not make it home and blew gasoline into my cabin while driving on the highway. Almost passed out, and am still fighting Kia to actually address the defective rod bearings. I personally would fight tooth and nail over a 5 dollar problem, but this is something they do nationwide and can cause serious injury or death. If it weren’t a 200 LB man driving the gasoline shooting into the cabin would absolutely cause a knockout. To the time of this report they are still trying to disregard the rod bearing issue and send me home with fixes to problems caused consequentially.

Filed May 15, 2026 · Engine, Transmission · AR

Issue 1: High oil consumption in the engine due to poor engine design, according to the auto repair center. 5 quarts of oil are added to the engine once every 2-3 weeks. All oil leaks were previously repaired, but oil is still burning off. Issue 2: The engine has misfired more than once, with a puff of smoke coming out of the exhaust. Issue 3: Twice in the past 1.5-2 years, multiple spark plugs have failed, causing a breakdown. This is a Theta II engine, but it is not in the class action settlement.

Filed Apr 21, 2026 · Engine · 160,000 miles · FL

The contact owns a 2016 Kia Optima. The contact stated that while driving 70 MPH, the check engine warning light illuminated. An independent mechanic was contacted. The vehicle was taken to an independent mechanic to be diagnosed. The contact was made aware of a misfire coming from the engine. The vehicle was not repaired. The manufacturer was notified of the failure but offered no assistance. The approximate failure mileage was 160,000.

Filed Feb 1, 2026 · Engine, Lights · VA

The engine is a problem and all I’m ever told us “ this vehicle is know to have engine problems. This is dangerous to have in the road. Kia is aware of this. Why sale the vehicle knowing this and not disclosing this info to the consumer upon purchase. There is no truth in lending. It’s plain sight robbery. What if I’m far from home and stranded because vehicle set fire or broke down in hazardous condition weather. I constantly needing oil changes because of this engine. The dealership is aware. They tell me to trade it in or get rid of it because it’s going to go for a fact. I’ve never missed oil changes. I put oil every time the oil indicator light comes on. Now for the 3rd time the check engine light is on. 2 times for misfire code. The vehicle engine holds sludge no matter how much you get oil changes. The mechanic told me this year make and model is known for this very fact. I want my money back. Kelly blue book don’t give enough. I was scammed into this car but I managed to pay it off. A car the sales person scammed me and wouldn’t take the vehicle back. I complained to the general manager. They always act like he wasn’t available. They kept claiming new ones started. After almost a year of those games I had to move and the case never got solved. But even when I complained their maintenance person stole my rims. They told me prove it. Just all bad experience. I just want my money. Even if they gave me another engine. It’s still going to be the same problem. A bad engine. 2016 Kia optima’s should not have been continuously sold with them knowing it has bad engines. Even the headlights don’t work. Very dim. Car smells like burning fumes when driving. Please please help. This isn’t fair lending practice. People trust them and they are dishonest sellers.

Filed Jan 9, 2026 · Engine · VA

Car is burning a lot of oil, took to dealer went through several tests and they claim burning 1.5 quarts was within limit for 1000 miles. Then started getting misfire codes and car went into limp mode a couple of times. They said to replace spark plugs because they were fouled and clean injection. Performed those requested actions, then 45k later getting misfire codes again, took to another dealer they said plugs are fould and clean injection again. Asked them to provide a permanent fix for the issue so the car does not keep fouling out the plugs and they said the only way to fix was to replace the motor. I asked, since you have no guaranteed fix why don't you replace the defective motor under warranty. They said because it is not locked up or throwing a specific code detecting a knock in the motor. So I said the motor will have to completely fail before a replacement would be approved they said yes (basically suggesting I somehow blow up the motor). This is wrong, a product under warranty from manufaturer and cannot be fixed without replacing the part should be covered. I do not know what my options are at this point, the milage warranty has run out and they will not do anything to fix it, just bandaids until it dies. the dealers would not put it in writing only verbally telling me.

Filed Dec 9, 2025 · Engine · OH

My 2016 Kia Optima is experiencing severe internal engine oil consumption that matches known issues Kia has recalled and extended warranties for. The vehicle loses 1–3 quarts of oil every few days with no external leaks. A repair shop found a P0304 cylinder 4 misfire, P0010 cam actuator code, and spark plug damage caused by oil entering the combustion chamber. They confirmed internal engine damage and abnormal oil consumption. The Kia dealership refused to assist due to mileage, even though this issue matches the engine defects covered under Kia’s litigation settlement and warranty extensions. The excessive oil consumption creates a dangerous safety risk, including engine stalling, loss of power, and potential engine seizure while driving. I am requesting the federal safety agency review because the vehicle’s condition is unsafe and part of a widespread engine defect.

Filed Aug 22, 2025 · Engine · TN

Engine began jumping during driving and loss power. No dashboard illumination warning lights and the temperature gage showed normal operating temperature. Car was not accelerating properly. Had to maneuver carefully to prevent being ran over. Engine light illuminated showing misfire. Replaced ignition coil pack and spark plugs. Driving again, car stalled. No dashboard warning lights. No high temperature on gauge. Narrowly missed being hit by a semi as there was absolutely no warning and we were on an Interstate bypass ramp with nowhere to pull over!! Towed car to dealership for diagnosis. Results: engine blown, turbos gone, and the catalytic converter is holding oil. Dealer is stating this is not covered under the extended warranty from Kia as its not connector rod bearing issues and that the piston rings failed. However, they stated the turbos got "too hot" and they failed. The gauges have never shown that the car was running hot. I have a sworn statement from my mechanic stating this is absurd and a valiant attempt to not pay for what would be the second warranty replacement of my engine. The piston rings failed as a result of the connector rod bearing failure. The "too hot" temperature that damaged the turbos was likely caused by the same bearing issue. The heat from the bearings unseated the piston rings and allowed the engine to dump its oil causing the engine to fail. I highly recommend that you open an investigation into these issues. The car not accelerating and losing power at interstate speeds is a very serious and dangerous issue.

Filed Aug 11, 2025 · Engine · 100,000 miles · MO

The contact owns a 2016 Kia Optima. The contact stated that while driving at 45 MPH, there was a misfire coming from the engine, and the vehicle was shaking. There was no warning light illuminated. The vehicle was taken to an independent mechanic to be diagnosed. The vehicle was diagnosed with engine failure due to piston rings failure, causing coolant intrusion into the engine. The contact was informed that the engine needed to be replaced. The contact stated that the ignition coil, cylinder #1, and spark plugs were replaced. The dealer was contacted, but had not diagnosed or repaired the vehicle. The manufacturer was not made aware of the failure. The failure mileage was approximately 100,000.

Filed Jul 18, 2025 · Engine · FL

Engine issue, it’s knocking loud and misfires. Engine light flashing and Car went into limp mode , will not go over 60 mph . I have changed the spark plugs, knock sensor, and had an oil change nothing has fixed my issue.