how do i adjust the idle speed

Hello, Avoid attempting to adjust the idle, as there is likely a different cause. Make sure you don't have any fuel leaks, and ensure the PCV valve is properly functioning. After that, check vacuum lines to make sure they aren't pinched, or pulled tight. Lastly, the idle air control valve (IACV) may be blocked, which would not allow the engine to receive enough air when the throttle body is closed. This can be checked from the IACV port, inside the throttle body. If you need help diagnosing the vehicle, send me your questions, but if you prefer to have the vehicle professionally diagnosed, here is a list of certified service centers in your area: http://repairpal.com/ford-within-10-miles-of-williston-north-dakota-58801