2018 Honda Accord: misfire or rough idle

Filed Nov 4, 2026 · Engine · 104,000 miles · CA

The contact owns a 2018 Honda Accord. The contact stated that while driving at 40 MPH, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. The RPM was elevated above 2,000 RPM, but the engine shuddered, and the vehicle lost motive power. The dealer was contacted and made aware of the failure. The vehicle was taken to the dealer, where it was diagnosed with a blown head gasket. The contact was informed that there was a misfire in cylinders #2 and #3. The contact was informed that there was coolant mixed into the engine oil. In addition, the contact was informed that the head gasket and the engine needed further diagnostic tests. The contact stated that the failure was a known failure with the vehicle. The manufacturer was contacted and made aware of the failure. The failure mileage was approximately 104,000.

Filed Oct 18, 2026 · Engine, Transmission · MD

My 2018 Honda Accord EX-L with the 2.0L turbocharged engine (K20C4) and 10-speed automatic has had a cylinder head gasket failure at approximately 111,000 miles. The vehicle has been maintained consistently. Starting in early October 2026, the vehicle began shaking violently under acceleration while the engine was cold, including when accelerating at highway speed and climbing hills. The shaking lasted for roughly the first 15 minutes of every drive. No check engine light or diagnostic trouble codes appeared. In mid-October 2026, a Honda dealership diagnosed coolant leaking past the cylinder head gasket into the combustion chamber and quoted approximately $5,000 for the repair. Replacement parts are on backorder with no estimated arrival date. Violent shaking during highway acceleration is a safety concern, and continued coolant leakage into the cylinders can cause further engine damage. In August 2026, American Honda extended head gasket warranty coverage to 10 years or 150,000 miles on 2018–2022 Accord 1.5T and hybrid models for the same condition: coolant entering the combustion chamber and causing misfires. The 2.0L turbo engine was excluded. A pending class action (Alcantara et al. v. American Honda, consolidated with Bissell v. American Honda, S.D. Cal.) alleges head gasket failure in Honda's 1.5L and 2.0L turbocharged engines. I ask that the federal safety agency investigate head gasket failures in 2018–2022 Accords with the 2.0L turbo engine, and whether this engine should be included in Honda's remedy.

Filed Sep 14, 2026 · Driver assistance, Engine · CT

I am reporting a recurring safety and mechanical issue with my 2018 Honda Accord 1.5T, which currently has approximately 128,900 miles. My vehicle has been experiencing shaking/rough operation and multiple warning lights while driving. Diagnostic scans have shown P0301 – Cylinder 1 Misfire and U0401-68. The ignition coils were replaced with original/OEM parts in an attempt to correct the issue. After the repair, the warning lights went away temporarily, but within several days the same warning lights and symptoms returned, and the vehicle again showed the P0301 cylinder 1 misfire code. I am concerned because the vehicle continues to shake and operate abnormally despite the repair. I have learned that Honda has addressed cylinder-head-gasket concerns involving certain 1.5L turbocharged Accord vehicles, which may cause engine misfires. However, I have not had my vehicle diagnosed with a defective head gasket, so I am not claiming that this is definitely the cause of my vehicle's problem. When I checked my VIN through the federal safety agency, it showed 0 unrepaired recalls. I am submitting this complaint so that the federal safety agency has a record of the recurring problem and can determine whether my vehicle's condition may be related to a broader safety defect affecting 2018 Honda Accord 1.5T vehicles. I am concerned about the possibility of the continued misfire causing loss of engine performance, loss of power, stalling, or otherwise making the vehicle unsafe to operate if the underlying problem worsens. I have photographs of the diagnostic scans documenting the codes and records showing the previous repair.

Filed Sep 11, 2026 · Electrical, Engine · NC

1>Engine failure: Around the time vehicle reached 148,000 miles on it, it blew a head gasket on cylinder 2. Coolant was in the cylinders. The vehicle would not accelerate and was misfiring. 2> Safety was affected as this occured on interstate 40 and caused the vehicle to slow to an unsafe speed. 3>Problem was confirmed by Morganton Honda- Morganton NC. 4> Check engine light.

Filed Sep 2, 2026 · Driver assistance, Engine · GA

I own a 2018 Honda Accord Sport 2.0T that has been consistently maintained through authorized Honda dealerships. On July 30, 2026, at 135,968 miles, I took my vehicle to Nalley Honda for a Blind Spot Information System warning and maintenance. The dealership performed a multi-point inspection and documented the spark plugs, cooling-system hoses, and fluid leaks as PASSING. I authorized approximately $1,231 in repairs and maintenance. Only days and approximately 202 miles later, multiple warning lights appeared. I returned to the same dealership. At 136,170 miles, Honda documented DTC P0302 (Cylinder #2 Misfire). The injectors passed an air-fuel test. The technician then noted pressure releasing from the cooling system despite low coolant temperature. A head-gasket leak test was performed and FAILED. Honda diagnosed a blown cylinder head gasket and recommended approximately $4,906 in repairs, including spark plugs that had passed inspection only days earlier. I am concerned about the sudden failure of a major engine component in a well-maintained vehicle, particularly so soon after a Honda dealership inspection. I have learned that other Honda Accord 2.0T owners have reported premature head-gasket failures. A failed head gasket can result in misfires, coolant loss, overheating, reduced engine performance, and potential engine damage while driving. I am requesting that the federal safety agency review this complaint along with similar complaints involving Honda Accord 2.0T head-gasket failures to determine whether a defect trend exists and whether an investigation is warranted.

Filed Aug 24, 2026 · Engine · OH

I am reporting a suspected head gasket/engine defect involving my 2018 Honda Accord Sport. My vehicle experienced multiple engine-related problems before ultimately requiring head gasket replacement and cylinder head repair. On July 27, 2024, at approximately 161,480 miles, the turbocharger was replaced. In September 2025, at 207,539 miles, my vehicle was serviced at Joe Morgan Honda, an authorized Honda dealership. During that visit, the Honda technician documented that the cooling system fluid level was low and that no external leaks were found. The technician documented that they suspected the head gasket was causing internal coolant loss over time. I was instructed to monitor the vehicle and was provided an estimate of approximately $4,400 plus tax for head gasket replacement. I specifically asked the Honda service advisor whether the head gasket could be repaired at that time or whether anything could be done to prevent the suspected problem from progressing. I was told there was nothing that could be done at that point other than monitor the vehicle. Within weeks, multiple warning lights illuminated on my dashboard and the vehicle began experiencing significant drivability problems, including hesitation, misfiring, and loss of acceleration. The loss of acceleration was particularly concerning because the vehicle did not respond or accelerate normally while being driven. I took the vehicle to Integrity Automotive on September 25, 2025, at 208,583 miles. The engine was checked, and the ignition coils and spark plugs were replaced. Despite those repairs, the vehicle ultimately required major engine repairs on November 8, 2025, at 210,230 miles. The cylinder head gasket was replaced and the cylinder head was serviced/repaired. The fuel injectors, spark plugs, and serpentine belt were also replaced, and the cooling system and drivability/performance were checked. Only approximately 2,691 miles elapsed between the Honda dealership documenting the suspected i

Filed Aug 23, 2026 · Engine · LA

Car losing power on the interstate and side roads Replaced spark plugs, replaced coil packs replaced fuel injectors after dealers diagnostic testing $2500 for those issues Vehicle still misfiring took in to another dealer head gasket need replacement $5200 quote

Filed Aug 18, 2026 · Engine · NJ

The head gasket is leaking coolant into cylinder #2. The car has misfired and has not been operable. The problem has been confirmed and diagnosed through the dealer. there were no prior warning lights to the issue until the car completely became inoperable from one day to the next.

Filed Aug 15, 2026 · Fuel system · AL

Unknown, all lights are showing on dash with "Emissions systems problems power may be reduced see dealer." After spark plug replacement about a month later raw gas smell, rough idling, and slight jerking continues.

Filed Aug 14, 2026 · Driver assistance, Engine · KS

The head gasket is failing and causing the engine to overheat and misfire. Its a repeating issue I see online and have taken it to a certified Honda mechanic multiple times. The first diagnosis stated that the biggest issue was the fuel injections. Now this second diagnosis shows the head gasket. It poses a great danger especially in highways, as it causes the car to decelerate on its own and rattles as if it's losing power. It will overheat when it is idling. The check engine light turned on a week after purchasing the car from a local dealership, and the dashboard lights were wiped from the system prior to buying the car a year ago. Now I'm looking at over 7k in repairment costs while still financing a car I believed was reliable.

Filed Aug 11, 2026 · Engine · MO

In July 2026, our 2018 Honda Accord required a head gasket replacement. Prior to the diagnosis, the vehicle began experiencing rough starts and engine misfires. While driving, the car suddenly lost power and would not accelerate beyond approximately 10 mph. After returning home and restarting the vehicle, its performance temporarily returned to normal; however, the engine continued to idle roughly. We had the vehicle scanned, and the diagnostic result indicated a misfire in Cylinder 3. The vehicle was taken to our local Honda dealership, where we were informed the head gasket failed and needed to be replaced. Given that the vehicle has fewer than 140,000 miles, we do not believe such a major engine repair should be necessary. Over the past 25 years we have owned multiple Honda vehicles, including Accords, Civics and CR-Vs well over 200,000 miles with our current 2008 Honda CR-V having more than 344,000 miles. None of these vehicles have ever experienced a head gasket failure or similar engine issue. We have never had such a significant costly repair, over $6,000. We are extremely disappointed that our 2018 Accord required such a significant repair at relatively low mileage. We have also learned of allegations in ongoing litigation Bissell v American Honda Motor Co, involving similar head gasket issues affecting Honda vehicles. Based on our experience and the number of reported complaints, we believe Honda should issue a recall, provide warranty coverage or reimburse affected owners for repair costs whichever benefits the customer. We respectfully request that Honda review our case and consider reimbursement or goodwill assistance for this unexpected and expensive repair.

Filed Aug 6, 2026 · Engine · VA

At 92,156 miles, my 2018 Honda Accord Touring (1.5L Turbo) suffered a catastrophic structural head gasket failure that caused dangerous engine instability while driving. The failure first manifested with a sudden eruption of multiple warning lights across the dashboard while the vehicle was in motion. Following a subsequent startup after a doctor's appointment, the vehicle began shaking violently due to immediate engine misfires. Driving a vehicle that is actively shaking and suffering from cylinder misfires in live traffic creates an unpredictable stall risk and an immediate safety hazard to myself and surrounding motorists. A certified technician at Ourisman Honda of Woodbridge pressurized the cooling system and physically confirmed that engine coolant is actively leaking directly onto the engine cylinder walls (Cylinders 1 and 2) due to a structural head gasket failure. This is a severe design defect that causes unexpected powertrain disruption on public roads.