I just put both a new alternator and a new battery in my 2002 Ford Explorer and it runs fine until I get to ta stoplight . Then I have to put it in neutral to keep it running. Have I accidentally hit a vaccum hose or what?
If you had bumped off a vacuum hose on this type of Ford then the idle would be high not wanting to die. If it was running properly before the replacement try this: Disconnect the battery, positive or negative it won't make any difference, turn on the headlight switch, wait at least 30 seconds, turn off headlight switch, reconnect the battery, set the parking brake, if park brake won't work then push and hold brakes pedal, start engine, put it in drive and turn on all accessories ie A/C, heater fan, headlights etc, let engine idle until it stabilizes, turn all accessories off that you turned on then drive vehicle at least 20 minutes so the ECM can relearn the vehicles parameters and your driving characteristics. If this procedure won't work then you should take it somewhere and have the codes checked there maybe pending codes that haven't turned on the light yet. The relearn procedure will pick up on a pending problem.