I recently bought another Crossfire. My son drove it home and he told me he had similar problems trying to keep up with me on the highway. Testing it myself at home, I found when I would aggressively accelerate and hit 3,000 RPM the engine would actually stop running. I put one of my scanners on the car and it was showing a number of strange codes which I was suspect of. The seller mentioned changing the Crank Position Sensor. I decided to install another one. I found the seller had not installed a Bosch CPS. I installed the Bosch sensor and it fixed the problem.