My sister has a 1997 ford expedition xlt she has been having problem with it running and starting it for a while know. The problem with keep it running is that if you let your foot off the gas pedal it dies and the other problem is she is having trouble starting it. Useally when she she has this problem it clicks when she turns the key and she wiggles the batterie cable and it starts but know when she trys to start it it clicks when she turns the key and she wiggles the batterie cable and it still does not start. What could cause this to problems?