2018 Mazda CX-5: misfire or rough idle

Filed Oct 13, 2025 · Engine · OH

Driving fine at low speeds (under 40mph), once I accelerate to highway speeds the engine misfires, check engine light flashes, Smart City Brake System Malfunction, Radar Malfunction, and car losses all engine power. Car just coast, lights and brakes still work. Check engine code moves around and will be on cylinder 3 sometimes and cylinder 4 other times. Able to replicate this issue multiple times. Serious safety concern.

Filed Aug 21, 2024 · Acceleration, Engine · FL

The issue started happening [XXX]. I was driving home and the car went into limp mode. Several errors came on the heads up display and on the dashboard. At first I could not go faster than 31mph, then it dropped down to 17mph, then to 7mph by the time I got home. 1.When accelerating from a stop light, car goes into limp mode and won’t accelerate almost stalling in the road. You must pull over, turn off the car and wait 5 minutes so error clears so you can drive again. 2.Car goes into Limp mode when going up a hill 3.Between 46-48 mph, car hesitates when accelerating 4.Between 56-60 mph, car hesitates when accelerating 5.Error Codes received per Lake Car Care: P2299, C1001, B1303 I brought the car to Lake Car Care and they replaced the spark plugs and coils as the codes said it was a misfire on Cylinder 1 & 2. This cost me $ 947.57. This did not fix the problem. The mechanic Todd took the car for a ride and it went into limp mode for him also. He could not figure the issue out after having the car for a couple weeks so suggested I take it to Mazda in Clermont. Mazda has had the car twice for over 2 months now and cannot figure it out. They replaced the ABS Module for $ 1284 which did not fix the problem. Replaced the injectors for $ 1426 which didn't fix the problem. They did a fuel compression test which came back fine and cleaned the catalytic converter which they said was clogged and this didn't fix the issue either. It is unsafe to drive this vehicle on the road as it does not accelerate so it is putting myself and others at risk. Mazda corporate has been called and case manager has been assigned but has been NO HELP to me at all. Photos are attached of all error messages, text messages with Mazda, repair receipts, etc. August 9th, Mazda told me they are at a loss and don't know what else to do, I haven't heard from them since. Please help. I am at a loss and don't know what my options are. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Apr 25, 2024 · Engine · NY

The cylinder head cracked and broke resulting in a massive oil leak that covered all the parts under my car and under the hood and engine which in result started to smoke. This is not only a major issue of extremely costly repairs but more importantly also serves as a major safety issue. This could had caused fire to the vehicle and also engine misfire resulting in engine failure while in drive and potentially lead to critical injury or death for me and my family. Mazda was aware of their poorly designed engineering for this critical and extremely important component and it is known Mazda recognized the issue by issuing a TSB. After further research there are numerous TSB issued for multiple engine failures with Mazda. It is also known that certain VIN number vehicles manufactured with this defect are commonly reported and have experienced this exact same issue within only a few years and or very low mileage. This is a major mechanical failure to happen to vehicles within a short time span of purchase and results in loss of customer trust and loyalty. As a first time car buyer I am deeply dissatisfied and disappointed with Mazda. I would not had purchased a brand new car if I would had known I would experience this only at 5 years and 71 thousand miles. My vehicle was inspected and diagnosed by a certified Mazda dealership. I was advised and informed that this is a huge issue that has happened with all customers. Mazda knowingly neglected the proper manufacturing and engineering for the cylinder head and other engine parts, which is the most critical component to any vehicle to function and operate. Lastly what is more concerning was that there was no warning signs such as lights or sensors that were triggered as warning of the issue and vehicle failure posing as another safety concern for drivers.

Filed Aug 22, 2023 · Driver assistance, Engine · MI

On 7/30/23, I was driving home from church, and was driving on the freeway in the fast lane when my 2018 Mazda Cx-5, that was only 5 years old, with only over 33.2K miles on it, started to stall. Thankfully, it didn't come to a complete stop, but slowed down tremendously, and had at least 5 malfunctioning lights come on all at once. The car wouldn't go over 25 miles afterwards. I was very thankful to make it home safely, but this was very alarming, since I never had any issues with that car, and always kept it very well maintained. For a car that was only 5 years old and had only 33.2K miles on it, to experience such a drastic problem, is very confusing. It was very concerning that the car almost came to a complete stop unexpectedly without any warning ahead of time, especially while driving in the fast lane on a freeway. I also took pictures of the malfunctioning lights that came on right after the incident took place. I had the car towed into the dealer the next day, and they told me that it was unusual that my engine would do that. They said that it needed a tune up earlier than expected. I was told that the 3rd cylinder was misfiring, and also when the engine isn't working properly, everything else in the car would shut down. Now, why would a car that's been very well maintained, with only 33.2k miles on it need a tune-up? And I always kept up with the oil changes on time. I found out that there was an engine recall on these particular models, but I was told by Mazda that my VIN # did not qualify; however, what I experienced, did fit the description of the recall. I've since then, decided to trade in the car, because I was just too afraid to continue driving it after this experience. I am however, very upset that I had to give up a car that I invested a lot of money in and took very good care of, and only had 33.2k Miles on it.

Filed May 23, 2022 · Fuel system · 15,000 miles · FL

The contact owns a 2018 Mazda CX-5. The contact received notification of the federal safety agency Campaign Number: 21V875000 (Fuel System, Gasoline) however, the part to do the recall repair was not yet available. The contact stated that while driving at an undisclosed speed, the vehicle experienced rough idling with the check engine warning light illuminated. The dealer was made aware of the failure but confirmed that parts were not yet available. The dealer informed the contact that he needed to pay out-of-pocket for a diagnostic test. The vehicle was not diagnosed nor repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 15,000. VIN tool confirms parts not available.

Filed Feb 10, 2022 · Engine, Fuel system · MA

There is no recall on this which is a huge safety issue. This has happened to me on highway several times and Mazda will not do anything about it. Very dangerous when you are going 65 on a highway! TSB Number 01-007/19- misfire P0304- of 4th cylinder. Recommendation to replace main silencer due to condensation accumulation in the exhaust baffle. Please search the TSB and misfire code I provided to learn more about it. If you are out of warranty. You are out of luck with Mazda. I will take upon myself to educate others where Mazda could careless to correct this or let the public now.

Filed May 13, 2021 · Engine · 38,650 miles · CA

Situation: driving uphill on hwy 120 on new priest road, big oak flat, ca, two lane mountain road. Slow car in front of me and a delivery truck tailgating. Slow car eventually moves aside in a turnout and I accelerate to open up space between myself and what I thought would be the truck but somehow the slow car returned to the driving lane ahead of the truck. I continue to accelerate to attempt to open up space between myself and the car behind me when I lost power, the car behind me moves to the opposing traffic lane to avoid rear ending my car that is running in degraded mode (accelerator has no effect, basically moving on idle power) and narrowly misses an oncoming car as I move towards the right edge of the right lane. Truck behind me has to brake hard to avoid rear ending me. There was no shoulder to pull over to at that location immediate location. I pull over a few hundred yards further at a safe location. Grade was perhaps 4% to 6%. Weather: hot 90 degrees speed: accelerating from 35 to 50 MPH (guess) diagnostic lights: smart city braking system failure warning, plus a lot of other warning lights lit including check engine light. Aftermath: I pulled safely over, stopped the engine, waited a while and restarted the engine and the car returned to it's normal driving behavior and completed my trip. Other information: this is the 3rd occurrence of this behavior. Each time I have had mazda look at the problem. 1st occurrence they replaced the cylinder coil, 2nd occurrence they replaced a spark plug for misfire. 3rd occurrence, to be determined.

Filed May 6, 2019 · Engine · 9,500 miles · OR

Vehicle went into limp mode while passing on two lane road. Cause was determined to be wrong logic in PCM for cylinder deactivation. This worng logic caused low oil pressure in the lifter during deactivation which in turn caused the rocker arm to become dislodged rendering the associated valve inoperable. There is no indication to the driver of if or when this happens. The driver is then driving the car in a very dangerous state. The problem arises when the the rpms become elevated to around 5000 rpms and above. At this point the computer senses trouble with that cylinder due to the air fuel ratio not being correct and throws the engine into limp mode. Creating a very dangerous situation if you are trying to pass or avoid something where you need the accleration. Extremely dangerous!! When I took my vehicle into my dealership they discovered the misfire on cylinder #4 and mazda had them remove the valve cover and inspect. Upon inspection they found a rocker arm had fallen off . According to mazda my car was the 19th that they had seen with this problem. My car was in the shop in oct. Of 2018. By the time my car was out of the shop that number had increased to 26. Mazda said the source of the problem was the wrong PCM programing. They stated they have 2 suppliers of pcms and one of their suppliers was using the wrong program. To fix my car they replaced the engine and reflashed the PCM to the correct program. I asked the dealership if they were going to reflash all of the vehicles on their lot that have this engine and they said they did not have permission from mazda to do this. I feel they should have done that because mazda admittedly does not know which cars have the wrong program and a simple reflash of all new vehicls would fix this situation. The number of these bad vehicles is increasng and many peple could be in danger. Mazda should recall asap