I have been getting these weird, I don't know what to call it except vibrations when on the highway. It feels like it's somehow connected to the gas pedal, definetly happens more when I'm slowing down, but also sometimes when I'm holding speed steady or speeding up. The car doesn't shake or anything, but I feel this movement and almost knocking under the pedal somewhere. Have had the car maybe a year and a half, the last few weeks I've been noticing it more than ever. Any thoughts? Thanks.