2019 Ford Mustang: misfire or rough idle

Filed Oct 21, 2026 · Engine · NJ

My 2019 ford mustang egoboost with only 59,000 miles has a cylinder three coolant intrusion. This is disappointing, as the only right way to fix this according to Ford, is to replace the whole engine. Nobody should expect to have to fix their entire engine. Now on cold starts coolant is leaking in to cylinder three, which is causing misfires and could potentially lead to a safety, risk. Ironically, there’s a lawsuit currently in place for this exact problem. This is a problem, sudden engine failure or stalling due to severe coolant intrusion introduces a dangerous loss of power while operating the vehicle at speed and could lead to a blown or locked up motor. Ford has kept this under wraps since the release of this generation of vehicle.

Filed Oct 13, 2026 · Engine · OK

Known engine coolant intrusion problem with the Ford EcoBoost engine. It misfires and was confirmed by a service center that a whole new engine was needed. Car shaking and rumbling-- gas smell. Afraid of it catching fire.

Filed Aug 18, 2026 · Engine, Transmission · TX

My 2019 Ford Mustang equipped with the 2.3L EcoBoost engine developed a check-engine light, rough startups, engine misfires/rough running, and some engine knocking. The vehicle had approximately 87,453 miles. I took the vehicle to an authorized Ford dealership for diagnosis. The dealer brought the engine to operating temperature, pressurized the cooling system to 21 PSI, removed the ignition coils and spark plugs, and inspected the cylinders with a borescope. The dealer documented coolant intrusion into cylinder #2 due to a failed cylinder head and recommended replacement of the complete long-block engine due to the extent of the damage. The dealer also documented diagnostic trouble codes P0300 and P0316 for misfires, along with P008A and P018C related to low-side fuel pressure. I am concerned that internal coolant intrusion causing misfires, rough operation and engine knocking could result in significant loss of engine power or engine failure while driving, creating a safety hazard, particularly at highway speeds or in traffic. Ford Customer Relations was notified but declined financial assistance because the vehicle is outside the factory warranty and stated that there is no applicable recall for my vehicle. The vehicle has not been repaired and is available for inspection. The Ford dealership's written diagnostic report and photographs of the cylinder inspection are available.

Filed May 23, 2026 · Engine · FL

Left for work. Started running funny, stalled-started-stalled-started on my street. Got on highway about 1/2 mile, check engine light & engine temp light came on. Got off highway and called a tow to SARASOTA FORD. Tech ran diag. for codes, codes found.: P1285( cylinder head over temp ), P0316(engine misfire ), P0304( cylinder 4 misfire ), P0303(cylinder 3 misfire ), P0302( cylinder 2 misfire ), P217( engine coolant over temp ),.. Tech removed spark plugs and saw coolant in cylinder's ( 2,3,4 ) with a bore scope. Ongoing problem I found out about after the fact with the ( 2015-2019, 2.3L EcoBoost .. "ECO-BOOM" motor ). Specifically between cylinder's 2 & 3... Was quoted a repair cost of over $10,000.00 -12,000.00 dollars. It's been next to my house for almost a year now. Bought the car used in JANUARY 2021 with my son with no explanation of the known problem. If known I would not have bought the car, 2019/FORD/MUSTANG/2DR CPE ECOBOOST FASTBACK. Diagnostics were done on 06/04/2025 at ... Incident happened around 05/30-31/2025, That's about all I got

Filed Apr 12, 2026 · Engine · CA

The car is using a lot of engine coolant and oil. It is also burning the spark plugs. The check engine light comes out 6k miles after I install new spark plugs and it starts shaking, misfiring, running poorly, not accelerating properly and blowing white smoke through the exhaust on cold start. I know the engines have a defect from factory that causes them to do this. It usually needs a new head gasket, block or engine. Please advise. I read a forum that referred me to this website. The car is well taken care of and has 115k miles.

Filed Apr 7, 2026 · Engine · WA

Description of the Defect: My 2019 Ford Mustang EcoBoost experienced a premature engine failure caused by internal coolant intrusion, resulting in the need for complete engine replacement. This failure is not related to routine maintenance or a head gasket issue, but rather a known internal engine design defect that allows coolant to intrude into the cylinders over time. The vehicle exhibited symptoms including coolant loss without visible external leaks, rough operation, and engine malfunction. Upon inspection by a Ford dealership, the failure was diagnosed as coolant intrusion into the engine, with the only repair option being long‑block (engine) replacement. Ford has acknowledged this failure mode in Technical Service Bulletin (TSB) 19‑2346, which documents coolant intrusion in EcoBoost engines and states that engine replacement—not head gasket repair—is the required corrective action. This bulletin confirms the issue is caused by an internal design flaw that develops over time. Why This Is a Safety Concern: This defect can lead to sudden engine misfires, loss of power, or complete engine failure while driving, which poses a serious safety risk to vehicle occupants and other road users. Engine failure at highway speeds or during normal driving conditions creates the potential for crashes, loss of vehicle control, or roadside breakdowns in unsafe conditions. The failure occurred at very low mileage (~36,000 miles), indicating a premature and abnormal engine defect, not normal wear and tear. Yes, it is available for inspection upon request. Yes, it is diagnostic and confirmed by AutoNation Ford Bellevue [XXX] Direct line: [XXX] No, prior warning and symptoms. First appeared on March 16, 2026. No recall exists despite Ford’s TSBs acknowledging the defect. Ford later redesigned the EcoBoost engine, showing awareness of the issue, yet owners are forced to pay for costly engine replacements after warranty expiration. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Dec 2, 2025 · Engine · FL

Have a 2019 Ford Mustang 2DR 2.3L Ecoboost with 59,500 miles which I took to the dealership with a code P0302 and P0304 present, cylinder misfire, observed coolant level low, performed borescope in cylinder 2 and 4, found coolant intrusion, recommend long block engine replacement which would have cost me $10,728.85. Concern is that the engine can stall suddenly and may cause an accident. Ford Motor Company knows about these kind of engine issues with Ecoboost engines and have not offer any reasonable solutions. Vehicle VIN is the following: [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 28, 2025 · Engine · PA

Check engine light on. Code is p0301 for multiple cylinder misfires. At startup I can hear coolant sloshing around and white exhaust. Coolant is leaking into cylinder 1. The Ford dealer says it needs a new engine. 2019 ford mustang ecoboost at 55k miles.

Filed Aug 21, 2025 · Engine · FL

On Repair Order #:[XXX] at Lorenzo Ford, the dealership technician documented the following: “Verified customer concern, DTC P0304 perform pinpoint test, inconclusive, perform coolant pressure test and found coolant intrusion into cylinder 4.” This confirms a coolant intrusion defect causing misfire and overheating — exactly the well-documented issue affecting 2.3L EcoBoost engines that is now the subject of a pending class action lawsuit (filed June 2025). INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 31, 2025 · Engine, Transmission · CA

My vehicle experienced a blown head gasket due to a faulty engine block design at 56K miles. The car started running rough for 10 seconds upon a cold start up and was also misfiring. This is due to coolant intrusion through the gasket and it got into cylinder 3 which could have caused catastrophic engine failure or worse.There are several class-action lawsuits against Ford for the defect.Ford has not taken any steps to address this issue with the ecoboost engines on 2015-2019 models. Additionally, Ford did NOT provide relief to me and I had to pay out of pocket to fix this.

Filed Jul 10, 2025 · Engine, Transmission · CA

My vehicle recently had a head gasket leak due to a faulty engine block design. I noticed one day the coolant was lower than it should be but nothing concerning, over a month or so it got progressively lower & the car would also sputter/misfire on startups from time to time. This is due to coolant slipping through the gasket & getting into the cylinder & oil which can lead to catastrophic engine failure or worse. Eventually I got a check engine light & was told it was a misfire after running a diagnostic on the vehicles OBD2. I researched what the issue could be &it became more & more apparent that it was a head gasket issue. The oil was contaminated & coolant was getting very low. Apparently it’s a big issue since Ford is now facing a class action over the defect. The vehicle also has some issues with the transmission, for example ill start the car up on a cold California morning 50°F & let it warm up before driving & when I go into reverse after the car will jolt hard as if you were backing up & hitting something like a wall, even in the afternoon when you start it from a cold start & go into reverse it will do it. Not sure why but it’s concerning to say the least. The transmission also feels confused when shifting, when I’m in 4th about to push fit it will get confused & revs will drop slightly before going up again to up shift, also when downshifting due to braking the shifts can feel a bit hard, especially when needing to stopping fast. The engine & transmission are the most importantly parts of a vehicle & without them working properly is something no one should have to face.

Filed Jan 3, 2025 · Engine · 42,000 miles · LA

The contact owns a 2019 Ford Mustang. The contact stated while driving at undisclosed speeds and attempting to accelerate, the vehicle failed to accelerate as intended but started decelerating instead. During the failure, the contact would pull over to the side of the road, shift to park, turn off the vehicle, and then wait a while before restarting the vehicle for the vehicle to drive as intended. The failure also occurred while attempting to accelerate while idling. The contact stated that for several months during the failure, the check engine warning light was illuminated. The vehicle was taken to the dealer to be diagnosed, and the contact was informed that there was a misfire in cylinders #2 and #3. The dealer reset the computer to remove the code. The contact stated that three days later the check engine warning light was illuminated again. The vehicle was returned to the dealer who detected a misfire in cylinder #1. The spark plugs, crankshaft sensor, and coil packs were replaced. The check engine light was no longer illuminated; however, the failure persisted. The failure became more persistent, and the contact was pulling over to turn off and restart the vehicle more often. The contact had decided not to drive the vehicle due to the consistency of the failure. The dealer was contacted and confirmed that the failure was common for similar vehicles. The dealer diagnosed that the head gasket had failed; however, it was not recommended to be replaced due to the failure recurring after the repair was completed. The dealer recommended that the engine be replaced. The vehicle had not been repaired. The manufacturer was made aware of the failure and filed a case. The manufacturer confirmed that there was no recall on the VIN for the failure. The manufacturer referred the contact to the federal safety agency Hotline to report the failure. The failure mileage was approximately 42,000.