pichon50

Maybe someone can help me. I dont know if it my driving style or if it is just now that I am noticing it. Lately when i accelerate harder than normal the car seems to stay a couple of seconds longer in second gear and than when it shifts to third the car lunges forward. It feels as if the car wants to shift to 3rd but can't for some reason. I can't remember this ever happening before until these last couple of weeks. Has anyone experienced this with their IS 300.