I have '06 Fx35. When cruising at 40-5 mph and then gently increasing speed, the vehicle hesitates, jerks a bit. I then increase speed purposely and it stops, the same happens at 60-65 MPH. I am suspicious of a head leak or maybe a bad FI. I have performed the required maintenance on the vehicle over the years and will be bringing the car in for repair/analysis. I am trusting the Forum to provide me some expectations. regards, Guido