2021 Ford Bronco Sport: misfire or rough idle

Filed Oct 26, 2026 · Fuel system, Transmission · OH

The contact owns a 2021 Ford Bronco Sport equipped with an 8F35 automatic transmission. While driving between 25 and 45 MPH under normal acceleration, the vehicle experienced repeated violent hesitation, jerking, and lunging 4 to 5 times in rapid succession, accompanied by rapid RPM fluctuations between 2,000 and 3,000 RPM. The condition mimics an engine misfire or momentary stall and loss of motive power during acceleration, creating an immediate safety hazard and risk of rear-end collision in active traffic. The vehicle was taken to an authorized Ford dealership (Cronin Ford North) on September 30, 2026. The dealership verified and duplicated the complaint on a road test, monitored PIDs, and officially confirmed that the torque converter clutch (TCC) was slipping. Despite confirming mechanical slip, the dealership stated in writing that there were "no relevant articles," overlooking the published Ford Special Service Message SSM 54797 for 8F35 torque converter shudder below 60 MPH. The dealership recommended replacing the torque converter and main control valve body for over $5,200. When the owner declined due to cost, the vehicle was released back into service without answering the owner's written safety inquiry regarding whether the vehicle was safe to operate with verified drivetrain slippage. Additionally, the vehicle has an open safety recall (25S76) for which Ford corporate confirmed no remedy or parts are currently available. The vehicle has not stalled completely, but the severe hesitation and surging persist under normal acceleration. The manufacturer has not provided a resolution.

Filed Oct 14, 2026 · Engine · AR

Vehicle had rough idle. Loss power. Loss engine coolant and oil and started pouring large amounts of white smoke from exhaust.

Filed Oct 5, 2026 · Fuel system · CA

I have had issues dating back to when I first got the car with rough idling and it turning off while idling. Most recently about 2 weeks ago experienced inability to turn the car on after fueling with gas. Rough idling and turning off while idling were also associated with gas filling. I took this car to Ford dealership multiple times. Check engine light came on associated with EVAP leak code. Ford dealership unable to diagnosis. I took to an independent mechanic who diagnosed in 10 minutes it is an EVAP purge valve malfunction and that likely this had been defective for some time. I reported this to ford and they refuse to compensate for this. I have seen multiple reports online of same issue with other ford bronco sport dealers. This failure seems abnormally premature and defective design. Concerning it results in loss of power of the vehicle as well.

Filed Sep 15, 2026 · Engine, Fuel system · 124,000 miles · OH

The contact owns a 2021 Ford Bronco Sport. The contact stated that while operating the vehicle, exhaust fumes and a fuel odor entered the cabin, and the check engine warning light illuminated. The engine misfired, and the vehicle hesitated while driving. Upon inspecting under the hood, the contact discovered black soot in the engine compartment. The vehicle was taken to a local dealer for diagnosis, where the dealer determined that the piston solenoid, catalytic converter, and driver’s side lower control arm and bushing needed replacement. The contact stated that the PCM was previously replaced. The contact associated the failure with the federal safety agency Campaign Number: 26V340000 (Suspension); however, the VIN was not included in the recall. The manufacturer was notified of the failure. The failure mileage was 124,000.

Filed Nov 13, 2025 · Engine · CA

We purchased this vehicle 02/2025. The salesman stated there was a 5 point inspection and the car was good on fluids oil and brakes. We questioned the rough idle and odd sound the car made and we were told that it was normal. 07/2025 a mobile mechanic came out and repaired a recall. He stated in his notes that the car had an oil leak but he could not determine where. Fast forward to now, my car has been needing oil more than usual since we have got the car. There is a leak but it does not leak on the ground. 11/11/2025, I contacted Big Valley Ford in Stockton CA with concerns about the oil depleting rapidly and how my check engine light comes on which tells me my car has absolutely no oil. I mentioned a recall I saw online 22S21 and Greg (the man I spoke with) stated that was never a recall for my car. He saw the oil separator was replaced in 2022 but it was not for a recall. Greg then told me to make an appointment to bring the car in for a diagnostic and then an oil change. They would then mark my car where the oil is and have me come back in a few days to see how far the oil went down. I asked how much and he said 225 for the diagnostic and 135 for the oil change. Convinced he was lying to me, I called Ford in Tracy, CA and they confirmed there was a recall 22S21 for the oil separator. This car has given me so many problems and this issue clearly was never fixed and they sold me the car this way.

Filed Apr 17, 2025 · OR

The vehicle sometimes ran a little rough while idle at drive thru. Then week later the push start did not work... engine turned over but not start. After 6 times it finally started and ran good on way home. Later that week, kept having traffic lights in town turn red... constant slow so stop and go. Vehicle started sputtering and stalled out in the highway and died in middle of road and would not start. Had to let it sit several minutes and it finally started. We immediately turned around and went home. Made appointment at dealership. Tried to start vehicle to drop off for appointment but would not start. Had towed in. They claim fuel pump replacement required. Drove home and ran ok. Next day power inconsistent and runs rough at start and slow speed with one push start did not work. Reporting since my spouse is in a wheelchair and can not walk. This vehicle is only one we have that my spouse can get in due to disability and I am seriously concerned if vehicle stalls out on public highway again it is likely to result in an accident and he gets seriously hurt. Never had a vehicle I felt unsafe to have my family be in before and do not think it is safe for this vehicle be on the highway.