I have a 2015 C7 ZO6. I've had it for a year. The last several months I have noticed significant power loss after the car is warmed up and at track event. In the morning after the car is initially warms it accelerates perfectly fine there is no hesitation off the line. But after driving for awhile I noticed that off the line performance is extremely bad very slow until it reaches 3000 RPM. Very significant after my last drive from Chicago to st. Louis stopping at a toll booth and accelerating from the toll booth the engine was very sluggish up until 3000 RPM and then it surged rapidly. I also had several occasions where the car wouldn't have to the red line in 4th gear going hundred miles an hour and just kind of got stuck at about 4500 p.m. . This car has 650 horsepower and 650 foot pounds of torque and should not act like this. I had trouble barely passing a stock Mustang GT. At Road America last year with the temperatures within 90 days at the end of the straightaway I managed to get close to 150 miles per hour. This year when the temperatures were in the seventies on several runs I could barely make it to 108 and wouldn't go any further. There was one occasion about a month or two before this, racing down the highway around midnight and the check engine lights were flashing and there was significant notice for loss of power. The off-the-line performance is quite noticeable as I said even with the traction control and stability control turned off so this is not the case of the traction control kicking in. The car also does not appear to respond at highway speeds when accelerating in 3rd or 4th gear, there appears to be a very slight hesitation for about a second before I feel the power. There's also a horsepower gauge on the dashboard which when a car runs normal will go all the way to the 650 horsepower mark when floored. But when I was having these troubles I noticed a horsepower jump to maybe 375 fluctuated a bit and drop down to about 350 with the car floored in 3rd or 4th gear. When I took the car to the dealer he test drove it for 3 or so days and said It felt normal and the codes that were stored when the check engine light was flashing were erased already. I am thinking something to do with the fuel delivery system, the supercharger, or a restriction somehow in the exhaust. Any ideas before I take it back to the dealer and tell them to fix this thing. Apparently if therer are comp. codes, everything is fine according to them. By the way there was no overheating issues the car was running anywhere between 222-250-280 on the very hot 90 degree plus summer days last year. The other instances were at night when the temperature was in the 70s with clearly no problems with too high engine temperatures.