Mitsubishi Repair: speedometer, speedometer cable, vacuum leak

Question
While driving home from work,my daughter noticed her speedometer wasn't working.  How does it work? Does it work off a fuse,or off the computer,or off a speedometer cable?  It's a 2000 Mitsubishi Eclipse. She also has a stalling problem,mostly when she stops at a stop sign or red light.
I would like some information on these problems before she takes it to the repair shop.

Any info will be a great asset.  Keep up the good work!

P.S.
   She also said her car bucks sometimes,mostly on hills.  

Answer
Ed: there is a cable for the speedometer, which is old, broken well needs some repair. When is the last time you or her did a tune up on the car? Or else have the fuel pump check might not be putting out enough fuel. Takes three things for a car engine to go down the road right, air, fuel and stark. How about having it coded too, might be a weak sensor someplace. Oh hey I would check for a vacuum leak also, these newer cars those vacuum hoses run a lot of things. :~) So some ideas for you. I wish I could say oh it is this or that. But I can only send out some ideas for you to check. Hope this helps some and good luck! ~Linda~