This sounds like a problem with the positive battery cable which losses connection when hot which is common.
Here are diagrams to help you see how to fix the problem. Its a bit of a job but I have seen this problem before.
Check out the diagrams (Below)
Please let us know what you find. We are interested to see.
Images (Click to enlarge)
Wednesday, August 31st, 2011 AT 2:55 AM