2016 Hyundai Sonata: misfire or rough idle

Filed Jul 13, 2026 · Engine · TN

Cylinder 3 misfire code and rough idle/driving car tries to stall out, engine is consuming a quart of oil every 500 miles and has 30psi compression in cylinder 3. Car only has 129k miles

Filed Apr 30, 2026 · Acceleration, Engine · SC

This vehicle has a major engine flaw; Hyundai USA KNOWS about it, and STILL will not issue a recall for EXCESSIVE OIL CONSUMPTION. First episode: October 2023 at 86,371 miles. Dealership replaced leaking valve cover gasket and changed woefully-soiled spark plugs. Still under manufacturer warranty, but I paid the balance. Second episode: FOUR MONTHS LATER (Feb. 2024; 89,078 miles), another limp mode and Check Engine lamp. The spark plugs are soiled again with oil, so the dealership changes the spark plugs again, instead of addressing the underlying issue - Excessive oil consumption. Still under warranty, yet I pay the bill...AGAIN. Episode Three: October 04, 2024. Hyundai Sonata goes into limp mode again with CHECK ENGINE LIGHT illuminating – cylinder 1 was misfiring. All spark plugs fouled again; all spark plugs replaced. Valve cover gasket was leaking, so that was replaced as well. Yup, I paid for the repairs out-of-pocket. Episode Four: May 02, 2025. Vehicle goes into limp mode again, with CHECK ENGINE LIGHT turning on. Another spark plug fouled up, so it was replaced. Ignition coil replaced as well. Episode Five: June 19, 2025. Limp mode and Check Engine Lamp illuminates yet again, so Hyundai of North Charleston (SC) initiates an oil consumption test. "...[3.5 quarts of] oil consumption is excessive...", yet Hyundai denies everything. Hyundai is actually admitting to an underlying issue but offers ZERO assistance.

Filed Mar 9, 2026 · Engine · OH

Vehicle started then stalled requiring tow. No initial illumination of warning lamps or messages. Findings upon inspection by independent service center: multiple cylinder misfires (P030100, P030300, P030400, P030200, P030000) and excessive debris buildup on vvt sensor screen. Car uses excess oil- a minimum of 3 qts per 600 miles. No warning lamps or messages occur when car is excessively low on oil.

Filed Jan 26, 2026 · Electrical, Engine · TN

Engine started rough idling and knocking. Took to a mechanic who found metal particulate in the oil and the engine spun a bearing.

Filed Dec 5, 2025 · Engine · GA

My 2016 Hyundai Sonata with the DOHC GDI Theta-II engine is experiencing severe engine oil consumption consistent with Hyundai's known TXXI/TXXC extended warranty defect. The oil pressure warning has flashed while driving or braking, the engine runs rough when slowing down, engine has made knocking noises, and there is smoke/vapor with a burnt oil smell when removing the oil cap after driving. The oil level drops rapidly between changes despite proper maintenance. This issue poses a risk of engine failure, stalling, or fire while driving. I have maintained the vehicle on time with all oil change receipts. A Hyundai dealership refused to perform the required warranty diagnostics even though this issue falls under Hyundai's extended warranty for Theta-II engines. This is a serious safety concern, and no corrective action has been taken.

Filed Jul 11, 2025 · Engine · CA

This vehicle has a faulty engine design which results in extreme over-consumption of oil. After an oil change, the engine will typically empty in less than a month, which is beyond a reasonable level of oil consumption. Side effects of this include other parts of the engine wearing down quicker, including the spark plugs, which cause engine misfires. Ultimately, this vehicle's engine design causes financial hardship to it's owners and poses a potential safety risk to those who drive in it. I believe Hyundai should do a recall to fix this faulty engine (with an engine replacement if necessary).

Filed May 24, 2025 · Engine · CA

While driving my 2016 Hyundai Sonata Hybrid SE (89,000 miles), a “Check Hybrid System” warning appeared on the dashboard, followed by a sudden loss of power. Shortly after, the engine began knocking loudly. A local mechanic scanned the codes and saw engine misfire and hybrid system faults. After clearing the codes, the engine ran worse and the knocking increased significantly. I had to tow the car over 700 miles from Whitehorse, Yukon, to the Anchorage Hyundai dealership in Alaska, which cost me over $5,000. The dealership said they hear engine knocking but refuse further diagnosis unless Hyundai initiates a goodwill assistance case. My car has a rebuilt title, but this issue appears to be similar to other known failures and recalls, such as Campaign 198 / the federal safety agency 20V746000. It is a serious safety issue — I was stranded in the middle of a remote highway. This appears to be a major defect, and Hyundai needs to investigate and support affected customers.

Filed May 18, 2025 · Engine · UT · fire

My car on the freeway started knocking. The check engine light came on. The car immediately caught fire. It is at the tow yard now. We just went through the oil consumption testing and the cleaning. I filed a report in November it failed for misfire and we paid to have the top rebuild. The car failed the oil consumption 1000 miles after the cleaning. We were told to continue to drive. We had 4 people in the car. I have the dash cam with the rod knock. The car has a check engine code. Hyundai needs to be held accountable.

Filed Apr 7, 2025 · Engine, Fuel system · CT

Car keep stalling misfire just started muffler sound smoke lack of power when driving

Filed Apr 3, 2025 · Engine · CA

After having the car for about a week the engine light came on at that time I took the car back to Carmax Service Department in Canoga Park. They scanned the car and they told me that it was misfiring. Carmax fixed the car. They had the car for the ten days. The day I received the car back, the engine light came on again. Took the car to my mechanic and he ran the codes again and he told me it was misfiring, again. He cleared the code and I again returned the car to Carmax, and explained to them what happened. I checked on the car couple days later and I was told that they drove the car for 30 miles and the engine light didn't come on. I picked up the car the next day On [XXX], the engine light came on, again. I returned the car back to Carmax, April 1st and talked to the Service Manager. I explained to him everything that happened. In each case, before returning the car or having the inspected, I did notice a difference in the way the car responded. Also, when I filled up with gas, the gas didn't fill up all the way and there was a clicking sound when driving. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Mar 12, 2025 · Engine · KY

The engine violently vibrates and no matter how much I get an oil change it burns so fast and I have to keep adding. It's not leaking, just burning. I plugged in a diagnostic tester and it said that the 3rd cylinder was misfiring. I haven't had the car for very long, and this is not normal. I take good care of it.

Filed Feb 13, 2025 · Engine, Fuel system · CA

I was driving a 2016 Hyundai Sonata on a mountain highway and it started to run rough and lose power dramatically when accelerating. A dangerous situation on a steep curvy highway that has many one lane sections. Shortly thereafter a dash light came on. There was no warnings or dash lights or symptoms prior to this incident. I took the vehicle to a mechanic and ran the code. It said there was a misfire in cylinder 3. Replaced the ignition coil and spark plug for cylinder 3 and it did not fix the problem. The mechanic then pulled the motor to check the valves. Valve 3 was burnt, had a hole and stuck open. The car had approximately 75,180 miles. Well within the warranty time frame of 10yrs or 100,000 miles for an original purchaser. The mechanic had the valve machined, and replaced the head gasket and reassembled the the motor. I picked the car up and drove it home. Within 3 days I noticed an oil leak under neath the car where the engine bay is. I took the car back to the mechanic and he diagnosed a hairline crack in the oil pan. After some research I came across a letter from the federal safety agency on a defect investigation of Hyundai/Kia oil drain pan assemblies. This is exactly what happened to my car! I have paid 3500.00 to fix a car that has less than 76,000 miles. Hyundai needs to do better.