One problem related to emission control has been reported for the 2011 Hyundai Sonata. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2011 Hyundai Sonata based on all problems reported for the 2011 Sonata.
I was driven on the highway in the 2nd to left lane about 70 mph, check engine light was on and all of the sudden I lost complete control of the accelerator pedal. I pushed it all the way down to the floor several times, no pressure, no control and obviously slowed down. I moved over to get to the right shoulder to stop and see what is the issue, luckily the brakes worked, but many cars were dodging me trying not to hit me. I didn't get in an accident, but sure close to being in one and high speeds. Frightening to say the least. I did make it to the dealer and come to find it is an emission part that failed that caused the car not to accelerate. I did get it fixed but was out of warranty, and past the federal emission reimbursement program of 8 years or 80k miles. I had about 80,200-500 miles on the car. Coincidence, don't know, I am still concerned driving the car, it could happen again! I am just glad I didn't get seriously injured or killed. I didn't get reimbursed for the part that cost $1,500. But I am very concerned knowing that this could happen to anyone with emission controls by the computer in your car. I tried to be proactive therefore the post complaint for others. I guess it takes collateral damage of people losing life for car companies and the wonderful federal government to take notice. Beware most new cars have these systems from what I am told.