Same problem, you need a new alternator. Period. Some will try to say it's other stuff, but you will just spend a fortune till you get a new alternator.See if your lights pulse at night, if they do and they will you need one.If you have a friend who knows cars or you think you are good at changing parts do it yourself. It is a 3 hour job. Or the dealer will do it for about $ 450.00So see if you can do it. $ 210.00 for a new alternator.SteveAnswerHow fast were you cruising and what is the rpm's when the car shuts off and then back on? these cars have a rev limantor wich at a certain rpm will shut down until the rpm's come back into range. if you are talking 90 mph or faster that is what is causeing your problems.IT'S A SAFTEY FEATURE!!!! Answerthe alternator guy may be right, but it could also be a vacuum leak, depending on when it shuts off, if it is shuddering on idle then i'd say vacuum*not a mechanic* AnswerThere are a few other things that can cause this...
Assuming you may have left out some details... If the car runs fine otherwise; smooth idle, smooth acceleration, etc: two possibilities that are common -
1. Computer is failing, fuel mileage will not be what it once was (by several MPG) and eventually it will not restart even with you turning the key.
2. Timing control module failing, no other symptoms... same end result as above: it will get worse till it fails completely.
Although there are other possibilities, these are the most common in Ford powered vehichles.