I have a2011 C30 T5-6 speed. I have a slight miss/rpm variation at all speed. It's like running out of fuel, but it never shuts off. I've replaced every possible item that's replaceable. Plugs, coil pacs, injectors, throttle body/with sensor, maf. You can set the cruise at 60, it stays, but you can feel the slight hesitation. The fuel filter is in the tank, with the pump. I've owned the car for 7 years. this just popped up in the past several months. Ideas?