Hyundai Elantra misfire problems

Filed Oct 7, 2026 · Engine · CA

2020 Hyundai Elantra, VIN [XXX], ~79,239 mi. On or about [XXX], while entering a parking lot at low speed on an incline, I pressed the accelerator but the car had severe power loss and then stalled. It would not move in reverse. All dashboard lights came on only after the stall. I restarted it; the lights cleared. It was towed to Westlake Hyundai, 3610 Thousand Oaks Blvd, Thousand Oaks, CA 91362; checked in Sep 29, 2026 8:59 AM. Dealer found engine oil below the low mark, no external leaks, DTCs P0302/P0304 (misfires cyl 2 & 4), and all spark plugs worn/fouled. They replaced the plugs and started an oil consumption test per TSB 23-EM-008H. Critical safety issue: the oil pressure warning light never illuminated before or during the stall, despite critically low oil. This removed my only warning to pull over safely. A sudden stall in traffic could cause a crash. The vehicle has the 2.0L Nu MPI engine covered by Recall 21V301 for defective piston oil rings causing excessive oil consumption and engine failure. My VIN is not included, but it shows the same failure. Vehicle is available for inspection. No police/insurance inspection. Manufacturer not yet inspected. Concern: engine defect and oil pressure warning system failure. Attached: Westlake Hyundai repair order/inspection. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 2, 2026 · Engine · 46,961 miles · CA

The contact owns a 2020 Hyundai Elantra. The contact stated that while driving 25 MPH, there was an abnormal rattling sound coming from the engine, with the check engine warning light illuminated. The contact pulled over to the side of the road. The vehicle was restarted but unexpectedly stalled. The vehicle was taken to an independent mechanic and was diagnosed with camshaft failure. The vehicle was towed to the dealer and was diagnosed with engine failure caused by a misfire. The contact was informed that the engine needed to be repaired. The vehicle was not repaired. The vehicle was taken to another independent mechanic and was diagnosed with camshaft failure. The manufacturer was not made aware of the failure. The approximate failure mileage was 46,691.

Filed Jul 11, 2026 · Electrical, Engine · CA

The control panel /radio panel has had a glitch or blacked out screen where it wouldn't come back on for a few hours and I could smell electrical or plastic burning after it did come back on after that the radio started changing channel on its own while screen glitched on and of with saturated static wrench on my dash comes on periodically. The tires pressure unit never has the same amount of air in it according to the gauge. Even though I have made it so that they were all equal several different times. The car feels like it misfires when that it's 9500° outside and you go for any sort of extended drive past 10-15, mi. When the air conditioner is on high, the fuel economy doesn't seem to match the way it's supposed to and some of the programming is missing since the last time it was serviced out of the control panel. Some options that we're supposed to have been there aren't there anymore and I'm pretty sure that when I use the remote to roll down my windows they're all supposed to roll down. Well only one of them does and it doesn't roll it back up the way it's supposed to when that it is foggy out. My camera system says that I'm about to get into a crash and starts blinking at me and beeping and flashing saying that I'm about to crash because my forward safety system or my rear safety system is not working properly. And yes I've let them know about these things My car has less than 25,000 mi on it and the problem started probably 3 months after I got it. When I first got it there was a bunch of little pits in the glass or I want to say hairline bubbles. I don't know what else to call them but they replaced my windshield. They didn't replace the back window that still has them

Filed Jun 29, 2026 · Electrical, Engine · CA

While operating my 2017 Hyundai Elantra under normal driving conditions at approximately 70,000 miles, the engine suffered a sudden, catastrophic loss of motive power and stalled completely while moving in active traffic without any prior warning. This severe stalling event occurred despite the vehicle being strictly and meticulously maintained according to all manufacturer guidelines and scheduled service intervals. Prior to the stall, the Check Engine Light illuminated. A comprehensive diagnostic scan completed at an authorized Hyundai dealership confirmed active trouble codes P0014 (Exhaust Camshaft Position Timing Over-Advanced) and P0017 (Crankshaft-Camshaft Position Correlation Error). The internal physical engine timing assembly and Variable Valve Timing (VVT) components slipped out of synchronization, forcing an abrupt, automatic engine shutdown while navigating active roadways. This failure created an immediate, severe safety hazard and high collision risk due to the sudden loss of vehicle propulsion, power steering assist, and vacuum brake booster pressure, leaving me vulnerable in traffic. This structural timing deviation caused chronic engine misfires and forced raw, unburned fuel directly into the exhaust stream. This unburned fuel completely fouled and destroyed the primary Oxygen (O2) Sensor due to heavy carbon contamination and extreme thermal stress. The failed sensor and incorrect valve timing totally disrupted the electronic control unit's air-fuel management, inducing the unpredictable stalling hazard and causing an immediate, automatic state emissions/smog inspection failure. Repairing this underlying manufacturing and metallurgical defect at the official Hyundai dealership required an extensive mechanical teardown and replacement of the timing components, costing approximately $2,500 out of pocket. This exact failure pattern, cascading O2 sensor damage, and diagnostic trouble codes match hundreds of existing complaints with the federal safety agency.

Filed May 22, 2026 · Transmission · NE

What component or system failed or malfunctioned, and is it available for inspection upon request? How was your safety or the safety of others put at risk? The ignition coil in my 2017 Hyundai Elantra Limited has failed multiple times over the past several years. This recurring issue has caused the vehicle to malfunction unexpectedly, creating safety concerns due to reduced engine performance, misfiring, and the potential for sudden loss of power while driving, which puts both myself and others on the road at risk. The failed component is available for inspection upon request. Has the problem been reproduced or confirmed by a dealer or independent service center? This issue has occurred multiple times with my vehicle. After researching online consumer reports and owner complaints, I found that ignition coil failures appear to be a common and recurring issue reported by other 2017 Hyundai Elantra Limited owners. Based on these repeated failures and similar reports, this appears to be a known issue affecting this model. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives, or others? I have reported this issue to Hyundai multiple times. Rather than addressing the root cause or issuing a recall for this recurring defect, Hyundai has repeatedly provided credits to assist with repair costs when the ignition coil fails. Despite the repeated failures and safety concerns, the underlying issue has not been permanently resolved. Were there any warning lamps, messages, or other symptoms of the problem prior to the failure, and when did they first appear? Prior to failure, the vehicle would experience rough starts, engine misfires, and poor performance. After these symptoms began, the check engine light would eventually illuminate. Once the warning light appeared, the vehicle became increasingly unreliable and would stall or shut off unexpectedly. On one occasion, the vehicle shut off completely while I was driving.

Filed May 22, 2026 · Engine · AZ

Engine has consumed an alarming rate of oil for years. I brought to a mechanic and they performed a $2,600 repair on engine. It ran fine for while and got much worse with oil consumption to the point that I needing to add oil monthly. It has been difficult to keep up on keeping enough oil in car and engine has now sustained damaged. There is no ticking or noise, but there is a loss of power and sometimes, the engine runs rough. I continue to drive it and add oil. But I have researched this is an apparent problem with the elantra.

Filed Apr 16, 2026 · Engine · IA

The check engine light came on at 101000 miles. I took it to the shop and the mechanic said there was no oil on the dipstick and he put in oil and said we need a new engine because it is knocking. We have noticed the vehicle has a rough idle now.

Filed Nov 16, 2025 · Electrical, Engine · GA · crash · 1 injury

Initial Fault Code: P0303 Replaced all 4 spark plugs and all 4 ignition coils. The check engine light extinguished momentarily but returned, logging P0303 and a new P0301 Replaced all 4 fuel injectors. CEL extinguished momentarily and then returned, logging P0303. Replaced the entire engine electrical harness. Concurrently, all related electrical components and connectors were meticulously cleaned with professional contact cleaner. CEL extinguished for significantly longer period of time, and then returned, re-logging P0303 and P0301. Thid suggested the ECU was "handshaking" with new components but re-logging the fault upon detecting the persistent core issue. A full compression test was performed. All cylinders reported results within specification. Using a borescope I inspected cylinder walls in piston tops. There was significant carbon residue buildup but nothing out of the ordinary for similar GDI engines. I still performed a PEA GDI specific chemical cleaning. It was a a little smoother afterwards, but the misfire persisted and CEL remained on. I also removed, cleaned, and tested common sensor faults, with no result. Also p0128 code and no start / electrical drain, and engine light started flashing numerous occasions had to stop the vehicle. I tried swapping the coils, but all that proved was that the coil was good, I did a power and ground test, it passed the connector had 12 plus volt power and a perfect resistance to static ground. The signal wire from the coil connector had perfect continuity to the ECU but had OL to chassis ground showing there was no short. A test light was used to see if anything was coming from the signal wire to the ignition coil and that test failed, there was no signal pulse. The diagnostic process has definitively proven a component-level failure inside the engine control unit. See attached file for more detailed information.

Filed Aug 8, 2025 · Engine · IL

I purchased my 2019 Hyundai Elantra from a third-party dealer (Mike Carlson Motor Company in Haltom City, TX) on [XXX]. I have kept the oil changed on a regular basis since I purchased it. At the time I bought the vehicle, I purchased an extended service warranty that was through Assurant/First Extended Service Corporation. [XXX], while out of state (over 640 miles away from where I purchased the vehicle) my vehicle started making a rattling sound from the engine. The mileage on my vehicle was 85,320. I called the warranty company and opened a claim. I was told since I was not in the DFW area and more than 40 miles from the selling dealer or any sister properties, I could take it to any shop that will accept warranty work. July 18, 2025, the vehicle was finally picked up by a towing company and taken to the mechanic. An estimate was created on 07/23/25, stating test system oil is full, has code p0304 (which I looked up and is a misfire in cylinder 4), engine knocking from rod and/or piston, will need engine. Claim was sent to warranty company 07/31/25 and was finally denied today 08/08/25. First, they said lack of maintenance however, they had copies of all receipts. Then they said denied because covered under Hyundai powertrain warranty. However, after speaking with Hyundai Customer Care, it wasn't sold PRE-OWNED CERTIFIED. Had to send proof to warranty company showing no factory warranty (sent signed SelectCertified Form signed date of purchase). Now it was denied again stating OPEN RECALL on vehicle would have to contact Hyundai. The nearest Hyundai dealership is over 1 hour or more away. I'm hoping tomorrow when I reach out to Hyundai they can shed some light on the situation. I've been stranded in Illinois (I live in Texas) since 07/16/25 and have made no head way to get the vehicle back on the road. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 3, 2025 · Engine · NC

Burning oil. Multiple misfires. Replacing spark plugs more often than should have to. Engine knocking.