I have a 2002 Hyundai Santa Fe, and in Jan 2011 my timing chain broke and I had to replace the engine. They place a 2005 engine in my car. I have had the my car back for a month and on my way home from work (with my 4year old in the car) the car started to accelerate! With my foot, I made sure the gas petal wasn't stuck, I was breaking but that wasn't slowing my car down fast enough, It just slowed the acceleration. I placed the car in neutral and pulled the e-break. It slow the car from 60 to 40 and started to accelerate again even with the car in neutral. I ended up stopping the car by turning it off (which locked everything up and fish tailed my car) I differently had a angle on my side by not hitting anyone. So here is my questions. Would changing the engine have anything to do with this? The mechanic that changed the engine is telling me its the brain of the car that caused this to happen. Did the brain of the car need to be replaced since the engine has now been changed and its a 2005 engine? Could this just be something that happened, or a defect? I'm just finding it hard to believe only a month after changing the engine, this happening had nothing to do with it. Before changing the engine there was never a issues with my car. It had always ran great.