I have a problem with starting my 91 ford

This clicking sound happens when your car is not getting enough power from the battery. A simple test is to turn on your headlights and look to see if they are bright or very weak. If they are weak, you know right away that you either have a weak battery or poor wiring connection from the battery. Remove terminals and clean them with a wire brush and reinstall. Try to start again and check if lights are now bright. If not, charge battery and try again. If that fixes it, keep a check on it and see if the battery drains again. If so, have your battery and charging system checked to determine which is the problem. Any garage can take your battery and run a test on it for you. If its good, then just go to the next step, which is checking for a weak alternator charging circuit with an amp meter.

Clean the contact surfaces on the battery terminals. If that dosent help, ask and I'll give you more stuff to look at.