I have a 93 Explorer 4x4 4.0L engine that won't stay running when it is put into gear. The enigne will idle forever and a day, but move the gear shift to forward or reverse and it dies almost immediately. Return the gear shift to Park and it will again idle just as normal. There are no codes that show up in the computer.
Any ideas about what might be wrong and how to fix will be greatly appreciated.
TIA