I have a 94 with a 5.0 and the 4r70w tranny and when I take off from low speeds or a roll it takes off in it's highest gear. If I let my foot off the gas and then press it again, it won't down shift. and when at a stop in drive my trucks idle bounces up and down and at take off it acts like it's a standard. And when I put it in reverse it just died. What's going on with it?