Ford Forum - Enthusiast Forums for Ford Owners - I need help! All experienced Explorer owners reply please?

Ever since I purchased my 1991 Explorer 4.0L V6, I've had nothing but problems with it. Recently, I had transmission work done...surprised? Anyway, the reason for the work needing to be done, is my car wouldn't go into drive. Well, they replaced my trans with a rebuilt trans. Two weeks later, I couldn't get my car into reverse. I took it in, and it was still within the 30day warranty, so at no cost to me. Obviously they didn't fix it because it won't go into reverse again. I figured out that at first it wouldn't go into reverse when I was having other problems with my car. With my foot pressing the gas petal all the way to the ground, my car wouldn't exceed 3000 rpms. Otherwise my explorer would go into reverse. Now this problem is permanent. I can't figure it out!! Just as well, my idle just miraculously one day was extremely low. When I first start my car, I have to keep my foot on the gas to keep it running for at least 5-10 minutes, otherwise it'll stall. If anyone can help me, you'll be my savior. Any and all suggestions are more than helpful!