Jeep Grand Cherokee misfire problems

Filed Nov 5, 2026 · Engine · NJ

September 1: The vehicle triggered diagnostic trouble code P0306 (Cylinder 6 Misfire). It was immediately taken to an independent mechanic where the spark plugs were replaced to address the misfire. September 30: The engine suddenly refused to crank or start. The vehicle was towed back to the independent mechanic. The technician diagnosed a completely blown starter motor and noted thick white smoke billowing from the tailpipe upon replacement. Further testing revealed that engine coolant had flooded into Cylinder 6. Present: The vehicle was towed to an authorized Jeep Dealership for a comprehensive engine teardown. The dealership technicians confirmed that both the cylinder head and the engine block deck are permanently warped due to extreme localized thermal stress. Dealership advised coolant was not low and no codes on the computer to show that there was overheating occurring. All oil changes were done at the dealership and stellantis don't want to help with the replacement of the engine goodwill offered 10,500 digital imaging says no my fault I drove it overheating Coolant not low per dealership and no lights how was I to know it was overheating

Filed Oct 19, 2026 · Engine, Transmission · FL

"I am filing this supplemental report to provide critical new technical information regarding a 2026 Jeep Grand Cherokee Limited Reserve. This vehicle has experienced recurring engine instability, including rough idling, jerking, bucking, and loss of power. Most critically, on September 22, 2026, the vehicle nearly stalled while traveling 25–30 mph through a busy intersection, creating an immediate and severe safety hazard. Following this incident, an extensive investigation by Douglas Jeep, Stellantis STAR technical assistance, and a manufacturer engineer revealed oil contamination inside the engine cylinders and on the spark plugs. This is a recurring issue; the spark plugs were replaced prior to the vehicle's delivery in August 2026 and were replaced again in October 2026. Despite the involvement of a Stellantis engineer, the manufacturer has failed to provide a diagnosis of the root cause of the oil contamination or a permanent repair. The vehicle has spent approximately 30 cumulative days out of service since August 17, 2026. I am reporting this as a systemic mechanical failure that poses a significant risk of sudden power loss during operation."

Filed Oct 13, 2026 · Acceleration, Electrical · AL

Jeep just died going down the road - idle is off - report from computer says misfire on cylinders and bad emissions. Also auto shot off doesn’t work and radio freezes up.

Filed Oct 12, 2026 · Electrical, Fuel system · PA

Vehicle: 2021 Jeep Grand Cherokee Overland, 3.6L V6 Incident Date: [XXX] Location: [XXX] Safety Complaint: On [XXX], while driving my 2021 Jeep Grand Cherokee Overland on [XXX], the vehicle suddenly lost accelerator response while traveling on the highway. The engine initially remained running, but pressing the accelerator pedal produced no response. Multiple warning indicators illuminated simultaneously, including the electronic throttle control, ABS, traction control, airbag, and four-wheel-drive systems. The vehicle also exhibited unusual electrical behavior, including unexpected activation of the high-beam headlights. The vehicle subsequently became completely inoperable and would no longer crank or start. The sudden loss of propulsion while traveling in highway traffic created a serious safety hazard and placed me at risk of a collision. This incident follows an extensive history of significant mechanical failures and repairs to this vehicle, including: Replacement of the cylinder head following repeated overheating and engine misfires. Complete transmission replacement following transmission-related failures. Replacement of the radiator and cooling fan assembly TWICE within approximately one year, most recently during a trip to North Carolina. Additional mechanical concerns, including a camshaft-related diagnostic trouble code. Despite these major component replacements, the vehicle continues to experience serious reliability and operational failures. These repeated problems have occurred despite attempts to address them through dealership repairs and manufacturer warranty assistance. Stellantis previously extended the vehicle's warranty as a goodwill gesture following earlier issues. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 18, 2026 · Engine, Fuel system · FL

Final the federal safety agency Complaint Vehicle information * Year: 2026 * Make: Jeep * Model: Grand Cherokee * Trim: Limited Reserve * Engine: Hurricane four-cylinder * VIN: [XXX] * Current mileage: 1,199 miles * Incident mileage: 1,181 miles * Incident location: Parking lot in [XXX] * Manufacturer case number: XXX * Dealerships involved: Sarasota Jeep and Venice Jeep Complaint title Bucking, jerking, rough running, unexpected forward movement, and stalling in Reverse Complaint description I am reporting a possible safety defect involving my 2026 Jeep Grand Cherokee Limited Reserve equipped with the Hurricane four-cylinder engine, VIN [XXX]. The vehicle repeatedly bucks and jerks during acceleration, including at approximately 5 mph in parking lots. It also runs roughly and has demonstrated unexpected forward movement. These problems affect the vehicle’s ability to accelerate and operate smoothly and may create a safety risk near pedestrians, parked vehicles, other objects, and surrounding traffic. On XXX, at approximately 4:49 p.m., in a parking lot in [XXX], and with the vehicle at approximately 1,181 miles, I shifted the vehicle into Reverse. The Jeep shook severely and stalled. After I restarted the Jeep, it ran very roughly, continued bucking, and jumped forward unexpectedly. This created a potential risk of striking another vehicle, pedestrian, or object in the parking lot. The vehicle also continues to buck and jerk at approximately 5 mph in parking lots, creating an additional risk of unexpected movement near pedestrians, parked vehicles, and other obstacles. On XXX, at approximately 6:22 p.m., I contacted Jeep Customer Care and reported that the vehicle had stalled when I shifted into Reverse and that it ran very roughly after restarting. The manufacturer case number is XXX. I previously reported the bucking and jerking condition to Jeep dealerships. A service advisor at Sarasota Jeep stated INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 15, 2026 · Engine · MO

Service engine light came on and code read misfire. Tech said that ignition coil one needs replaced and it needed a tune up. They replaced all ignition coils, spark plugs and intake manifold gasket with tune up. Tech said that coolant looked low and checked the reservoir. He said there's a lot of chunks and dried out looking coolant in the reservoir. Recommended a coolant flush at the dealership. Tune up cost almost 1000 dollars. A few days later my teenage son was driving on the highway at 70 mph and out of nowhere a engine overheating warning flashed and the temperature went all the way up and then down and back and forth. My son had to try and get pulled off of the busy highway while overheating. Car was blowing out white smoke. He was stranded over an hour away from home. Had to have car towed. Was told by the mechanic the next day that the plastic oil cooler had cracked and the oil got into the coolant. Causing the engine to fail at only 104,807 miles! Cost for a new motor was 10,400! Shop said he just had the same thing happen on another vehicle with the same engine the week before mine! I had to pay out of pocket for the new engine. Obviously there's a safety defect in the plastic oil cooler causing several people to experience the same thing happening! There was no warning before the oil got into the coolant. Why is the same thing happening to so many people but nothing is being done about it? Having to replace the engine at 104,807 miles is insane. How many times does it have to happen before they recall the problem?

Filed Aug 18, 2026 · Engine, Transmission · GA

My 2013 Jeep Grand Cherokee equipped with the 3.6L Pentastar v6 has a persistent cylinder 2 misfire (P0302). The cylinder 2 spark plug, ignition coil, and fuel injector have already been replaced, but the misfire continues. Diagnostic testing with a scan tool confirmed that cylinder 2 accumulated 61 misfires during a single test while cylinders 1,3, 4, 5, and 6 recorded zero, and the misfire monitor reported " Fail this trip" the vehicle can appear to drive normally despite the active misfire. I became aware that Chrysler issued warranty bulletin x56 concerning the 3.6L left cylinder head on certain 2011- 2013 vehicles including select 2013 Jeep grand Cherokees. I contact a jeep dealer and advise that my VIN is not included in that warranty extension. I am reporting this because my vehicle is experiencing a similar cylinder specific misfire concerns and I believe this condition should be documented and investigated.

Filed Jul 2, 2026 · Engine · FL

#2 cylinder misfire code P0302. A known problem with this engine. A compression test reveals a common defect with this engine

Filed Jun 17, 2026 · Engine · WI

* Upon normal driving the vehicle suddenly began to run rough. At that point the engine light came on and began flashing. Yes, it is available for inspection * I was traveling at highway speeds with my two young son's in the vehicle, when out of nowhere we experienced a major loss in power, Forcing us to get to the far right lane and off on the next exit. * The problem has been Confirmed (Passenger Side intake camshaft has 5 out of 6 lobes significantly worn off. .119" of material missing as well as 2 holes on cylinder 6 piston. * It was inspected by and independent mechanic who discovered the damage to the camshafts and the piston. It was suggested that I return the vehicle to the dealer as it would be needing a new motor seeing as the damages were premature and catastrophic in nature. Upon initial inspection at the dealer, they failed to identify the 2 holes in cylinder 6 piston. Suggesting that the "said holes" were nothing other than flaked carbon deposits. * There were no warning lights or any symptoms that would have indicated anything was wrong.

Filed May 28, 2026 · Engine · NY

Cylinder Misfires OBD-II code P0303 Engine Overheats after changed thermometer Fuel in the coolant system Coolant leaking from exhaust