Fuel pump is located in the trunk on the left side you have to remove the interior panel
Should be a label posted either on door jamb or on fuel cap filler door
Most likely, it is in the gas tank. Any local auto parts store can confirm this.
Follow the + battery cable - should either be in the inner fender or on top of the starter
take it to a good mechanic or a ford or merc dealer and they have to clear it for you
Could be a bad coil, plug, or injector. Start with the coil first.
More than likely the gears are stripping on the door lock actuator and will soon fail to work.
your loosing idle pressure check your vacume lines ans throttle sensor
The crown vic is more popular its the same car basically but the merc is considered higher end the crown is cheaper to buy
12 and 13 are idle speed controller malfunctions. 74 indicates that the brake pedal was pushed while reading the codes.
Make sure parking brake is adjusted properly and not partially engaged and then try changing transmission fluid and filter (had a similar problem)
With a reader. You can get one at an Auto Parts store.
wiper motor bout worn out. my 1998 merc does the same. replace ya wiper motor.