2018 Hyundai Sonata · symptom sheet
Check engine light or misfire
- 66owner reports
- 37,291median miles
- $3,722median quote
- 1involved a crash
Newest report Jul 6, 2026 · checked Oct 2, 2026
253 of the 373 complaints on this car are about the engine. 66 of those describe misfire.
Tick what matches of 66 reports
Misfire on other Sonata years
Report counts are for each model year on its own, so a newer car has had less time to collect them. Model years with too few reports of it for a sheet: 2019, 2021, 2022, 2023, 2024.
What this problem usually is
These reports start with the check engine light. Many describe the engine running rough or shaking at idle, a P0300-series code, or a catalytic converter code. A worrying number say the light was flashing. Owners often list ignition coils or spark plugs already replaced, and the light coming back afterward.
What got replaced
Owners who name the part that was replaced mention the spark plugs (11 reports), the sensor (10 reports) and the ignition coils (3 reports).
Recalls and investigations
No recall on the engine covers the 2018 model year as of Oct 2, 2026.
NHTSA investigations into the engine on the Sonata
Loss of motive power. Closed dec 12, 2023.
Engine fires. Closed feb 5, 2024, led to recall 23V-877.
Non-crash vehicle fires. Closed dec 22, 2021, led to recall 20V-061.
Non-crash vehicle fires. Closed may 10, 2019, led to recall 18V-907.
Scope and timeliness. Closed dec 22, 2021, led to recall 17V-226.
Charging system failures. Closed oct 31, 1994.
What owners paid
5 of the 66 reports quote a price. Each dot is one quote. The middle half runs $800 to $5,000.
When it happens
The middle half of failures fell between 9,400 and 86,500 miles, from the 41 reports that gave a mileage.
Is this a known problem?
The manufacturer has sent NHTSA 10 service bulletins or notices for the 2018 Hyundai Sonata that deal with this problem. Newest first.
Federal rules make a manufacturer send NHTSA a copy of any notice about a defect that goes to more than one dealer or owner. Most of these are service bulletins, the repair instructions manufacturers send to dealers. NHTSA generally leaves safety recall bulletins out of this file, and recalls are listed separately.
If you are servicing an 8-speed vehicle with a âCheck Engineâ light on and one or more of the DTC listed, follow the service procedure and replace the related solenoid and harness.
If you are servicing an applicable vehicle with a âCheck Engineâ light on and one or more of the DTC listed below, follow the repair procedure and replace the related input/output speed sensor and harness.
Applicable vehicles with 2.0L T-GDI and 2.4L GDI engines may experience the Check Engine warning lamp illuminated with DTC P1326 and/or engine may exhibit Abnormal Noise or No Crank/No Start condition.
Certain vehicles with 2.0L T-GDI and 2.4L GDI engines may experience the Check Engine warning lamp illuminated with DTC P1326 and/or engine may exhibit abnormal noise or no crank/no start condition related to connecting rod bearing wear or damage.
6 more on the 2018 Hyundai Sonata page.
What owners wrote
“My car is consuming oil. Hyundai knows this is happening with the theta II engines. I was told to bring it in and do an oil consumption test which shows my car is consuming 1 qt oil every 406 miles but was denied help due to it being high Mileage and not under warranty. My car has now started misfiring due to cylinder 1 & 2 consuming oil.”
Filed Aug 7, 2025
“Check engine light keeps coming on got it looked at , certain parts replaced & itâs still on something to do with the air filter”
Filed Jul 31, 2025
“The engine shuts off, doesnât start, check engine light flashing, losses power, jerks while driving it, i will get it up yo speed then will shut off or wonât move.”
Filed Jul 4, 2025
“The engine stalls when driving, loses power, hard time to start. It uses an extensive amount of oil. Losing power/stalling can result in accident or fire in my engine. Yes check engine light came on said it was coils/plugs changed them 2xs already. Took it to a mechanic was told thereâs a recall on engine itâs a valve that is not getting air through that can potentially case a Fire in my engine.”
Filed Apr 22, 2025
Should you keep driving it?
This page can't tell you that. 1 of 66 reports involved a crash and 1 people were hurt. Owners who file are the ones who had a bad experience, and nobody checks their reports. If the problem affects steering, braking, power or a fire risk, treat it as a safety fault and have it inspected before a long or high-speed drive.
File your own report with NHTSA. Complaint counts are how a problem gets an investigation. How reports land on this sheet.
Guide Which lights mean pull over now? Warning lights by color and urgency
Other problems on this car
- Engine failure, knocking or rod bearing 88 reports
- Burns oil or oil level rises 75 reports
- Engine stalls or loses power while driving 53 reports