2025 Kia Carnival Engine Problems

I was on the on-ramp getting on the highway and whenever I started to increase speed and try to get over into the next lane, I noticed the car all of a sudden jumped a little bit and then it started consistently jumping in the check engine light was flashing, and I couldn’t keep the car over what ended up being 50 mph anytime I tried to go over 50 mph. The car jumped in was shaking pretty pretty aggressively I was able to finally make it to a gas station at the very next highway stop and after I shut the car off and turn it back on it seems like it was OK, but I’m still very scared to drive it. I then took it to the dealership to have them check for any store or pending codes because after we had stopped and turned the car back on it no longer had the check engine light on, and the dealership was not able to locate any stored codes in the system to see what it happened nor were they able to replicate the issue that we had found. Is a rec out on my vehicle, but no remedy is available and notices will not be sent for another month and a half at this point I am extremely uncomfortable driving my vehicle as I have young children and anything with a fire hazard is not safe.

I was turning onto a main thoroughfare fare, and the van was slow to accelerate, Engine light briefly blinked, then went off, and then when I was on the interstate I had to pull over the van was running rough. Once I went back on the road, the steering wheel was shuddering and finally the engine smoothed out. This has happened more two other times to me.

On 6-9-25, for the second time in the 10 weeks that I have owned my new 2025 KIA Carnival it has failed to accelerate beyond 30 MPH after pulling away from a traffic light. The vehicle displayed a warning that The Speed Limit Was 30 MPH and would not accelerate beyond that speed. The speed limit was not 30 MPH. I was able to pull onto a side street and take a photo of the warning, I took the vehicle and the photo to Boniface-Hiers KIA on 6-10-25. The dealership was not able to determine the problem but thought it could have some connection with the cruise control system. Once again I was lucky not to be rear ended by the car behind me.

On April 22, 2025 my Kia Carnival Ex would not accelerate more than 30 mph after pulling away from a traffic light. A warning appeared on the dash display saying The Speed Limit Was 30 mph and the Kia Carnival would not go beyond 30 mph. The Speed limit was Not 30 mph. I took the vehicle to the Boniface-Hiers Kia dealership on April 24, 2025. They could not find a problem but did re-set the computer for the transmission. I was very fortunate not to have been rear ended by another vehicle.

TL;DR : Vehicle engages limp home mode without any notification to the driver that it is in limp home mode and doesn’t generate any codes for technicians to identify why the vehicle went into limp home mode. During oil changes, a significant amount of residual oil remains in the engine. When the lube tech fills the oil using the recommended amount, engine is actually over full of oil as indicated on the dip stick. The vehile will start and run fine for a while. Later however, an oil pressure sensor will detect the over full status and put the car into limp home mode. No check engine light, no oil light, no indicator saying it’s in limp home mode, and when the service tech investigates, no code thrown for the issue. A manual checking of the dip stick will reveal the oil is over full. The fix is to drain oil to normal levels as shown on the dipstick. It isn’t a defect considering that it’s reasonable to expect a vehicle to be operated with the correct amount of oil. A future software update for the oil sensor to throw a code for the tech would be appropriate.