hey, i just noticed this today, that my entire engine, and the rear of the truck moves whenever i apply throttle or brake. its slight, and all visable screws i can see are tightened as far as they'll go, and it still moves. i disconnected the throttle return spring and that cured the throttle problem, but it still does it when i push on the brakes. is this normal? ive only had 6 tanks through, on hard pavement, no wheelies or anything. should i be concerned?