35nomoon

Hi new to the forum, I need help for my problem. I have 93 mustang 351w 5sp when I start the car and put into 1st gear the rpm is normal but once I start to drive and come to a stop in 1st gear the rpm rev's up to 2000-5000 rpm's and will not go down. But if I come to a stop in 2nd gear the rpm is normal, I've checked for leaks and there are none, I've changed the throttle bodies and the same thing with each. I've changed the accelerator cable and nothing so if anyone has any ideas to what is going on I greatly appreciate the help. Thanks