When my 98 Kia Sportage MT is in neutral and I am coasting the car idles rough as if it's about to stall. After I stop idles is smooth. When I disconnect the speed sensor the problem stops. This will happen if I am moving in neutral just slightly, like the coast to stop at a light (1mph). I have replaced MAF, IAC, Fuel Pump and fuel pr. Anybody seen this or know how to resolve?