2017 Hyundai Santa Fe: misfire or rough idle

Filed Sep 27, 2026 · Engine, Transmission · MD

Immediately following the mandatory Hyundai Servie Campaign Update 9C2-ECU THETA 11my vehicle began exhibiting severe hesitation, very rough idling, jerking at slow speeds and when gear changes, difficulty going up inclines and almost feel at times as though it is about to lose power which poses life threatening situations especially when turning into traffic. I have reported it to the dealers who never once test drove the vehicle but said to me that they did and could find no problem, however they did make me pay for repairs which never fixed the problem. I returned three times with the same issue. They recommended a Fuel Induction Service and a Auto Trans Service. Spark plug change. Igniton coils change. Nothing worked!

Filed Sep 8, 2026 · Engine · PA

-The primary mechanical failure is a burned exhaust valve in Cylinder 2, which has resulted in 0 PSI compression and a persistent engine misfire. This severe top-end valve degradation occurred as a direct consequential result of a chronic, underlying defect in the engine's internal oil-delivery and consumption systems. The vehicle is currently fully assembled, intact, and available for immediate inspection upon request at Brown-Daub Hyundai. -The vehicle suffered a sudden, severe loss of motive power while operating in traffic due to the cylinder drop, triggering a sudden transition into a dangerous operating state. The extreme oil consumption rate (burning 5 to 6 quarts of motor oil every 3,000 miles) created an ongoing, severe risk of sudden highway stalling, catastrophic moving component seizure, and potential engine bay fire due to extreme internal operating friction and chronic oil starvation. -Failure has been confirmed by two independent automotive facilities: Independent Confirmation: On XXX, [XXX]’s Service Center performed a diagnostic scan and an engine compression test, formally documenting diagnostic trouble code P030200 (Cylinder 2 Misfire) and verifying 0 PSI compression in Cylinder 2.Dealership Confirmation: On XXX, the service manager at Brown-Daub Hyundai executed a formal electronic and mechanical inspection under Repair Order #XXX, duplicating the failure and logging active trouble codes P0301, P0302, and P0128. -Symptoms first appeared progressively through an accelerating, severe oil consumption defect, which was documented during multiple routine maintenance: XXX oil consumption (115,865 mi): XXX (119,601 mi) no external leaks: XXX (125,502 mi) excessive oil consumption:XXX (135,116 mi) excessive oil consumption:XXX (133,022 mi) P0420 Cat Code: XXX (approx. 137,000 mi)engine rough-riding, shaking, & violent misfires began, preceding the mechanical breakdown INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 15, 2026 · Engine · MA

After having the Service Campaign 9C2 ECU SOFTWARE UPDATE FOR THETA II EMISSIONS IMPROVEMENT, TSB 26-01-013H-2 done, my vehicle started having driveablity issues. On a normal, cold start the engine's RPMs go up really high, so I take my foot of the gas and the revs drop, almost stalling the car, and then the car bucks. I put my foot back on the gas pedal, and the engine revs really high again and takes off. If I try to drive normally, the car bucks and runs rough. My car also revs a lot higher during highway driving, than it did before the update. All of this is also causing terrible gas mileage. My car did nothing like this until I had the 9C2 update.

Filed May 24, 2026 · Engine · CA

The engine in my 2017 Hyundai Santa Fe Sport equipped with the 2.4L Theta II GDI engine is experiencing severe excessive oil consumption. The vehicle consumes approximately 2–2.5 quarts of oil every 1,000 miles despite multiple repair attempts and dealership-performed combustion cleaning procedures. Hyundai Motor America and the dealership documented the condition under PA #[XXX] and recommended engine replacement. Hyundai Motor America advised me in writing that the vehicle should not be operated in its current condition because of the excessive oil consumption and pending engine replacement. Excessive oil consumption creates a risk of sudden engine failure, engine seizure, stalling while driving, and potential engine fire if oil levels drop unexpectedly. Because the engine rapidly loses oil between normal service intervals, the vehicle may become unsafe to operate without warning, placing myself, passengers, and other motorists at risk. The defect was confirmed multiple times by Capital Hyundai in San Jose, CA through two official Hyundai oil consumption tests. The dealership documented oil consumption of approximately 2–2.5 quarts per 1,000 miles and submitted the results to Hyundai Motor America under PA #[XXX].The dealership also performed multiple repair attempts, including spark plug replacement, fuel induction cleaning, combustion chamber cleaning, and repeated oil changes, but the excessive oil consumption continued. Prior symptoms included: Check engine light illumination, Cylinder #4 misfire condition, Engine noise, Excessive oil loss between oil changes, and Oil level dropping significantly within short mileage intervals. The check engine light and misfire condition first became severe enough to require dealership diagnosis on or around [XXX], when the vehicle was towed to the dealership. The excessive oil consumption issue was formally documented beginning [XXX] during Hyundai’s oil consumption testing process. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6

Filed May 1, 2026 · Engine · 87,000 miles · AR

The contact owns a 2017 Hyundai Santa. The contact stated that while driving at approximately 55 MPH, the vehicle stalled and hesitated to accelerate while the accelerator pedal was depressed. The check engine and check engine oil warning lights illuminated. The vehicle was taken to a local O'Reilly's, where it was diagnosed with ignition coil #3 misfire. The vehicle was not repaired. The vehicle was towed to an independent mechanic, where it was diagnosed and determined that the engine needed to be replaced due to severe engine oil consumption. The vehicle was then to a local dealer, where it was diagnosed with abnormal engine oil consumption, and the dealer determined that the engine needed to be replaced. The vehicle was not repaired. The contact stated that the vehicle required an engine oil refill 800-1,000 miles before an engine oil change was due. The contact related the failure to several unknown Hyundai TSBs. The manufacturer was made aware of the failure, and a case was filed. The failure mileage was approximately 87,000.

Filed Feb 4, 2026 · Engine, Fuel system · CA

I currently owned an 2017 Hyundai Santa Fe FWD with the 3.3 V6 Engine with approximately about 136,000 Miles. We were driving into Vegas when we heard the knocking Engine Sounds. Immediately we called the Dealership in Vegas advising them we were going to TOW the vehicle in. Once we get the Vehicle towed over to the dealership, we waited till the following Monday where it was authorized to have the engine replaced. We were so glad about that. The vehicle was going to be completed by early January and we got the news the Vehicle was completed but now having misfiring issues due to Faulty injectors. I was advised that this was not covered due to the mileage. This was an non issue when I turned in the vehicle to Hyundai. I made several attempts to contact my Case Manager and this was again denied due to the Mileage. For a vehicle with less than 140K miles and being less than 10 years old, we are very upset with this process and for Hyundai knowing that there were concerning issues with both the Fuel Injectors and Engine.

Filed Dec 17, 2025 · Electrical, Engine · AL

While driving- in total movement- the car completely shut off. Without any prior warning or indication. Immediately after, the car restarted, drove a couple blocks over, continuing to shut off while driving. It was then towed. How was your safety or the safety of others put at risk? The warning lights did not appear until AFTER the car quit. They all came on & flashed & quickly went back out. Uncertain which component misfired or is affected- possibly related to an engine or fuel/ cylinder failure. Car is at mechanic for inspection. Our safety & lives were in critical jeopardy as the vehicle stopped without warning while driving in traffic congested area. It is unknown if this is a known issue or if this situation has been replicated however the current mechanic facility has experienced the same issue with this vehicle. Also strong odor of gas was experienced during shutoff.

Filed Aug 9, 2025 · Engine · AZ

My vehicle we bought from carvana has been jerking/misfiring and now with no warning on freeway it wouldn't give power stalling. There was no warning nothing no lights came up. I drive my kids in this vehicle I've taken it to multiple mechanics they say they couldn't find why it's jerking and it must be a manufacturer issue. I looked online and yes lots of issues with the make and model recall about the crankshaft sensor cause these issues!!!

Filed Dec 26, 2024 · Engine, Transmission · NC

T3G Campaign 2017 Hyundai Santa Fe Sport AWD, 116000 miles. Purchased from a dealer in VA [XXX]. Never would have purchased if engine issues had been disclosed. The letter re:T3G campaign went out to dealers/service managers from Hyundai (of which I have a copy) is dated for October 2019. We never received any information regarding a T3G campaign. We took my car to the dealership on 12/16/24. (Valdese, NC). In 5 hours, they said they ran diagnostics & found the P0302 Misfire code. Without running further tests, they adamantly claimed there was a dead cylinder & the only fix was to replace the engine. Note: Spark plugs were replaced 2 weeks before this visit on Dec 1, 2024. They refused to listen to my concerns about the T3G campaign. Said vehicle didn't have that issue. That they couldn't run the tests because the P1326 code wasn't present (but it was in Sept). They didn't do anything about the current open recalls. They said they didn't have time. Corporate confirmed that my vehicle has had the correct service campaigns completed to qualify for the T3G campaign. I have called corporate twice-No response. We are very upset over the lack of care and solutions. We gave consent for work & nothing was done. The service manager was practically shouting that this car would leave me stranded, it wasn’t safe to drive, & that the only option to fix was to replace the engine/get rid of it. I was basically told it wasn't worth fixing. Putting a new engine in would equal than the car is worth at trade in value. No one can give me a guarantee that a new engine (even brand new from the factory) would not have the same problem that is happening now. Make this right by immediately authorizing an engine replacement for my vehicle to include a loaner vehicle & tow charge cover. I am aware of the class action lawsuit from 2021. Hyundai refuses to issue a recall for this engine issue. Please see attached letter for more information. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 1, 2024 · Engine · NH

(Feb 2022) As with all the years before, vehicle passed inspection without issue. (April 2022) 2017 Hyundai Santa Fe went in to the dealership to have fixed the recalled Auxiliary Canister Kit at 73k miles. Before this, there were no issues ever with my vehicle. (June 2022) Within a month and a half of the fixed recall, my car started to exhibit issues—without warning while driving on the highway, vehicle stalled and lost control of all functions. Luckily I was able to coast to the safety of the breakdown lane. Vehicle was towed to dealership who replaced battery and alternator. Vehicle seemed better for a short time after this, but ultimately around 6mo later trouble began again (January 2023) This time throwing codes, car stalling when accelerating on highway. Dealer replaced multi fuse, changed oil & filter, reset reminders and topped off fluids. Told us to drive for a few thousand miles to determine how much oil is burning. Brought back in May 2023. Engine light is on now. When on highway vehicle misfires. Had VCTS replaced, Crankshaft & Camshaft sensors replaced, spark plugs 2,4 & 6 replaced Oil level checked and was deemed “ok”. Ultimately, dealership recommended engine replacement, engine failed completely rendering vehicle inoperable/useless. Reached out to Hyundai for help, as well to make aware of engine problem, met with “not our problem”. Researched heavily for other vehicle owners with similar issues, found many actually! Hoping this reaches the right people for more help.

Filed Jan 29, 2024 · Engine · WA

Noticed a slight loss of power on a 4 hour road trip. When we stopped for gas the vehicle was shaking at lower rpm and the engine light came on at that point. I took it to a mechanic within 45mins of noticing the issue and it was scanned and a few other tests. Mechanic said cylinder 6 was misfiring, spark plug was covered in oil and compression test showed less than 20 psi. He said we were lucky to make it into town like that and we did not get stranded as there is poor service where we were. I had to get the vehicle towed approx 300km and sort out rides for my family along with a vehicle full of hockey gear and a weekends worth of clothes food. The problem has not self corrected. I will be taking it to my local mechanic to get a 2nd opinion. Currently the vehicle will continue to sit in my front yard until Hyundai wants to fix it for free.

Filed Mar 27, 2023 · Engine · 162,000 miles · PA

The contact owns a 2017 Hyundai Santa Fe. The contact stated that while driving at an undisclosed speed, the vehicle stalled. The check engine and oil pressure warning lights were illuminated. Additionally, the vehicle experienced rough idle. The contact related the failure to the federal safety agency Campaign Number: 17V578000 (Engine And Engine Cooling), however, the VIN was not included in the recall. The dealer was not notified of the failure. The vehicle was not diagnosed nor repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 162,000.