I am having a vibration, which I can feel in the steering wheel, but appears to be coming from the engine or transmission. It occurs between 2000 and 3000 RPM. If I go above that RPM range, it stops. It happens in 2nd through 5th, but never seemingly in first. It is worse if I am in a higher gear and just trying to maintain speed rather than accelerating, or if I am decelerating in gear. If I push in the clutch, it goes away. If it were only speed related I would thing CV's or halfshafts, or something at the wheels, but it is definitely RPM related. I can't check my codes because my ODBII port doesn't work properly, it has some kind of short or something, it will register momentarily, but then goes away. I'm thinking possibly injectors, or maybe something in the engine control system. Has anyone else ever experienced this? Any insights?