i dont have many vibes in my truck any more, just a few from my front tires but i am worried about the sound i get when i let off of the gas. especially on the freeway...it sounds like a grinding sound that is coming from the engine, it also gives off a very slight vibe that i cant tell what it is...its quite odd. i just cant put my finger on it...does anyone know of what the noise could be? i am scared to drive it on the freeway but it also does it a little bit around town... i need it cuz its my DD. can someone help me out?