 When I step down somewhat forcefully - but not necessarily to the floor - on the gas pedal, there is 1-2+ second hesitation or delay in acceleration or power, or what I call a “dead spot,” before there is any noticeable pickup.Basically, this Hybrid just “coasts” at its current speed for these 1-2+ seconds before any noticeable pickup is felt. Very dangerous situation, if you ask me. This occurs every time and it doesn’t matter if it’s from a dead stop or if I’m traveling at 10, 20, 30, 40, etc. MPH & depress the accelerator pedal - either somewhat forcefully or to the floor – the car just coasts at its current speed for about 1-2+ seconds before any noticeable acceleration is felt. I find this to be a VERY DANGEROUS and UNSAFE situation, especially when trying to get out of a tight spot in traffic, merge into fast moving traffic on the Thruway, pass someone, etc. It appears that the onboard computers are trying to figure out what do to before the engine and/or motor kicks in. Also, when braking normally, car “shudders” at times; brakes lock up or grab suddenly or don’t grab enough. Additionally, at other times, when brake pedal is NOT even depressed, there’s a feeling the car is slowing down and/or there’s a thumping sound. Very strange happenings on this Hybrid for I never had it on my non-hybrid 2008 Sonata.: Another major problem with this Hybrid is the shortfall in Hyundai’s advertised gas mileage numbers, which was another big reason I bought this car.  This 2015 Sonata Hybrid Limited was advertised to give me and others 36 MPG City/40 MPG Highway/37 MPG Combined. I won’t go into trying to parse the City or Highway MPG but I should by now, on my 6th tank of gas, get at least the 37 MPG Combined value.  However, my average for 12,569 miles (5/28/15--12/31/17) was only 30 MPG or 7 MPG LESS (or 18%) then Hyundai advertised I would get.Hyundai got fined/penalized for over $750 million a few years ago for overstating their MPG estimates, Hyundai didn’t either care, learn their lessons or made so much in profits that the $750 million was just a “cost of doing business.”For shame, Hyundai. You let me down...and let down many others down too. This will be my last Hyundai. I just hope I survive and not get killed when I try to get out of a tight spot.  BB