2021 Honda Accord: misfire or rough idle

Filed Oct 11, 2026 · Engine, Transmission · AL

I bought my Accord in February of 2026 with only 79k miles (now at 93k). 3 days after purchasing all of these warning lights popped up regarding emissions, brake system, power steering, etc. I brought it back in and they said that it needed a new fuel injector on cylinder one (which didn’t fix the issue). I have replaced all 4 spark plugs and kept up with maintenance since it has been in my ownership. Now I’m having issues with the car going in limp mode, decreased acceleration, decreased mpg, and constant misfire codes! I do not feel safe in this car anymore since it has almost left me stranded as well as it disabling the safety features which could put me at risk. Honda desperately needs to fix this issue seeing as it’s putting their customers at risk, along with others on the road. the federal safety agency please do something!

Filed Sep 23, 2026 · Engine · 43,881 miles · PA

The contact owns a 2021 Honda Accord. The contact stated that while her son was driving 55 MPH, the vehicle shut off with several warning lights illuminated on the instrument panel. The contact's son pulled off to the shoulder of the highway and had the vehicle towed to a dealer. While at the dealer, the mechanic discovered coolant leaking into cylinder #2, causing an engine misfire. The dealer replaced the head gasket. After the repair, the failure returned immediately upon driving the vehicle home from the dealer. The vehicle was taken back to the dealer and the failure persisted upon return of the vehicle. While checking the repair order, the contact discovered that the service report was blank. The dealer was unable to duplicate the failure or determine the cause of the issue. The contact was not notified of the issue after retrieving the vehicle. The manufacturer was notified of the failure, and the contact was provided a case number. The vehicle remained with the dealer unrepaired. The failure mileage was 43,881.

Filed Sep 10, 2026 · Driver assistance · SC

Vehicle started flashing all lights on dashboard. I drove it for awhile and then it eventually went off. A few days later same lights came back on a car started misfiring. Was told by Honda that is was the Turbo that's going bad. Today is just cut off on me. Luckily there wasn't anyone behind me. I see a lot of people are having these same issues and a recall should be put out immediately.

Filed Jun 21, 2026 · Engine · TX

The vehicle suffered an unexpected loss of engine compression and dropped into a dangerous Limp Mode while driving due to a Cylinder 3 Misfire code (P0303). The manufacturer dealership misdiagnosed the mechanical issue using an unrelated 2.0L engine service bulletin (SB23-026) to clear the error. Six months later, the dashboard completely illuminated again with code P0299 (Turbocharger Underboost) caused by progressive pressure and compression loss across the 1.5L turbo engineering components. Upon post-visit inspection, engine fluids were found severely depleted. This ongoing engineering failure causes a sudden loss of vehicle motive power on public highways, creating a severe, recurring safety hazard that mirrors the active federal engine defect class-action litigation against American Honda Motor Co. This has happened 4 times with all the lights on my dash coming on Dec 2025, May 2026, June 2026 (2x)

Filed Jun 4, 2026 · Engine · TX

I am filing a complaint regarding the premature head gasket failure on my 2021 Honda Accord, which failed on May 28, 2026, with only 89,000 miles on the vehicle. A head gasket is a critical engine component that should last well beyond 89,000 miles under normal driving conditions and proper maintenance. I purchased this vehicle because of Honda's reputation for reliability and longevity, and I am extremely disappointed to experience such a major engine failure at this mileage. After researching the issue, I found numerous reports from other Honda Accord owners experiencing similar head gasket failures, particularly in newer models equipped with the 1.5L turbocharged engine. Many owners report engine misfires, coolant loss, overheating, and costly repairs at relatively low mileage. This suggests there may be a broader issue affecting these vehicles rather than normal wear and tear. My vehicle has been properly maintained, and I did not expect to face a repair of this magnitude before reaching 100,000 miles. The cost of replacing a failed head gasket is substantial and places an unfair financial burden on owners who reasonably expect Honda vehicles to provide dependable service. I respectfully request that Honda review this matter, investigate the growing number of similar complaints, and provide assistance with repair costs. I believe Honda should stand behind its products and support customers who experience premature component failures. Thank you for your attention to this complaint. I look forward to a prompt response and a fair resolution.

Filed May 8, 2026 · Lights, Seat belts · CA

I bought my vehicle around May 2024. Initially, everything seemed fine. However, I noticed that my car was starting to slow down and would enter limp mode, preventing me from exceeding a certain mileage. Subsequently, all the lights on my dashboard began flashing, prompting me to pull over and call a mechanic shop. I had all the necessary maintenance and repairs performed as per the plan. After starting the vehicle, all the lights turned off, and it drove smoothly. A few weeks later, all the lights came back on again, and nothing showed on the OB2 Reader, which I thought was odd because something shouldve popped up if all the lights on my dashboard was going all crazy. The mechanic said the same thing and maybe thought it was the battery, sensors going bad, or even the wiring. But he checked everything and said he didnt find any issues. So I went home and the lights on the dashboard stayed on for 30 seconds and then turned off after I started the car. The lights turning on all at once on the dashboard became more frequent and this time, the check engine light illuminated, indicating a misfiring issue. I took the vehicle to a mechanic shop for a thorough inspection, and they made a few minor adjustments. However, two months later, the same problem recurred. All the lights came on again, and the vehicle misfired once more, accompanied by the check engine light. Upon further investigation, it was discovered that the issue was a head gasket leak. Additionally, the seat belt alert for the passenger and rear seats, as well as the child car seat, failed to function properly.

Filed Mar 24, 2026 · Engine, Transmission · DE

Driving on the highway, my dashboard lit up like a Christmas tree. Car started having white smoke at tail pipe. Check engine lit blink 5 times. Had 4 kids under 14 years old in car. Almost got hit trying to merge over. Turns out misfire cylinder 4. Head gasket. Only 81,000 miles. I have owed 5 months. Car currently at Honda, they want almost 4,400 to repair. But apparently, Honda is aware of these HEAD gaskets going prematurely, in 1.5 l. and has done nothing about it. I do not have the money to repair this car on top of how dangerous it was to be driving on the highway.When this happened.

Filed Mar 12, 2026 · Engine, Fuel system · NC

I am writing to file a complaint on the service that was provided at Vann York Honda. On February 17, 2026, I was returning home from work and my car had a hard idle at start up. I was able to drive it home without issue. The next day, February 18, I got in my car and I had another hard idle start with many check engine codes appearing on the dashboard. I drove it to Vann York Honda in High Point, North Carolina for service. I was told it was a faulty fuel injector causing the problem and that it needed to be replaced. I left the car there over night and paid for the service; approximately $3,000. I got the car back on February 19. On February 20, I again had a rough idle on start up. I brought the car back to Vann York Honda and advised them that I was experiencing the same issue as before. The mechanic brought it to the back and advised me that he could not find anything wrong with the vehicle and that it is running fine. I expressed my concerns with the vehicle and he stated that without a error code or check engine light being on, it would be difficult to diagnose. The technician and the advisor said to keep driving it until a light comes on saying there is a problem since they could not find an issue. in the following 2 weeks, I had regular rough idles on start up and the fuel efficiency dropped approximately 6 miles per gallon. When I filled the car with gas, the fuel range dropped from 540 to 370. When I called about that issue, they said they reset the computer when performing the previous service on the vehicle and it is taking time for the computer to "learn" the car again. On March 6, I brought the vehicle back to Vann York Honda due to many check engine codes appearing on the dashboard. On the way to Vann York, the service advisor called me and stated that she would be reaching out to Honda Corporate to see about Honda paying for some of the cost of this service. My wife and I drove into the service bay and I spoke with the service adviso

Filed Mar 9, 2026 · Engine · CA

I am reporting a serious safety concern involving my 2021 Honda Accord Sport SE. The issue began at approximately 78,000 miles when multiple warning lights suddenly appeared on the dashboard while driving. At the same time, the vehicle began shaking and had difficulty accelerating. The engine felt unstable and the car struggled to gain speed. I immediately took the vehicle to a mechanic where it was diagnosed with an engine misfire on cylinder 3. The spark plug and ignition coil were replaced. After this repair the vehicle appeared to run normally for a short time, but the exact same symptoms returned shortly afterward. The vehicle again began shaking while driving and experienced loss of power and poor acceleration. This creates a serious safety concern, especially when merging onto highways or driving in traffic where sudden loss of power could lead to an accident. After researching this issue, I discovered numerous complaints from other owners of 2021 Honda Accords describing the same symptoms that ultimately resulted in blown head gasket failures. These complaints appear in the federal safety agency database and other consumer forums. The pattern of engine misfires, shaking, and loss of acceleration appears to be consistent across many vehicles with similar mileage. Despite the number of similar complaints, there are currently no recalls associated with my VIN. I believe this may indicate a broader manufacturing defect affecting these vehicles. I am requesting that the federal safety agency investigate this issue further to determine whether a safety defect exists that could require a recall or other corrective action.

Filed Feb 5, 2026 · Engine · CA

Financed a used 2021 honda accord sport in April of 2024 with 68,671 miles. About a month ago, with no warning signs of any sort such as overheating etc...my car did not want to start, finally started but was sputtering with a rough idle, my dash lit up with like 7 or more warning lights. Including a flashing check engine light. All the were safety warnings from braking system not working, to power steering to emissions failure, etc... and to take to dealership. Got the car to a local mechanic to get a diagnostics reading and was told I had a misfire in cylinder 2. Replaced the #2 coil and spark plug. Thought everything was fine until picking up my daughter from school and then all those warning messages lit my dash up again including the flashing check engine light. Car started sputtering and went into limp mode. Lost power and by the grace of God was able t9 coast off the major Blvd away from traffic and out of harms way. Very, very scary. My life literally flashed before my eyes. Not only my life was in danger but my daughters along with other drivers around me. So I took it back to mechanic and he ran diagnostics again still had a misfire. He could not pin point the exact problem. Took it to the dealership and they confirm it was a faulty head gasket between CYL 2 and water jacket. And they quoted me a price of $5,998. Which i can not afford. And feel Im not responsible for catastrophic major mechanical failure. I maintenance my car regularly thru the dealership so they have record of me properly maintenancing the car. Head gasket failure at 80,000 miles is absolutely unheard of. Until I started researching and come to find out this is a design flaw made by Honda. I was flabbergasted with the amount of people with the exact type of problem. Im afraid that even after repairing this problem that it may happen again down the line. And that would be putting my life in danger. Vehicle is still at dealership being that I can not afford the repairs.

Filed Feb 4, 2026 · Engine · CA

Starts Vehicle at cold start and notice right away engine turbulence, engine light flashing, lost some coolant and white smoke. Scan vehicle for codes, engine misfire #2.

Filed Dec 18, 2025 · Engine, Fuel system · 74,000 miles · AL

The contact's girlfriend owns a 2021 Honda Accord. The contact stated that while his girlfriend was driving at an undisclosed speed, the check engine warning light and several other unknown warning lights illuminated. Additionally, the contact stated that the engine was slightly misfiring while driving. An independent mechanic replaced the spark plugs and the ignition coils at the residence; however, the failure recurred 3 weeks later. The mechanic inspected the vehicle but could not determine the cause of the failure. The vehicle was taken to the dealer, where it was diagnosed with head gasket and fuel injector failure. The contact was provided an estimate for the repair. The vehicle was not repaired due to the cost. The manufacturer was not notified of the failure. The failure mileage was approximately 74,000.