i am writting this for my army brat daughter, she recently purchase a very clean 86 5.0 with low mile. recently it is devoloping a problem with the fuel system. when you shut off the car the fuel pump does not always shut off. she replaced the fuel pump rely and it did not help now she wants to replace the ign. switch .  i dont thing that is the problem . she need help to be able to fix this problem properly. any one have any idea what the problem is. we have been told that it is the fuel pump its self..
???????????????? help please she can not afford to just parts change till she finds the problem.  

I'm not an electrician, but the first step I would take is to attain a service manual for the year vehicle she has (Ford will be the best, after that I like the Haynes or Clymer manuals). Study the electrical diagram...the ignition switch is going to be a player...the fuel pump has to get power and it will be through the switch...do some basic tracing to locate your power routing, and then start the process of elimination...what ISN'T shutting off when the ignition switch is shut off? That would be my first move...hope this helps...
mrclean03