[Doug Tatham]

Check the positive battery cable. There are often several wires going to the post connector. It sounds like one of them is loose. Also check the wires that goes to your starter. There are two wires. A thick one and a small one. The small one comes from your ignition, the thick one goes to the battery. Make sure both are tight. If not this, then it may be the ignition switch. My bet is on the battery connector though.