Mysterious electrical problems!

[imtheneal]

So the other day I went to turn on my X5 and noticed that it started but it was a weak start as well as rumbling of the engine. I turned it off and tried to start again and no luck. Tried to jump and no go. Checked all the fuses and nothing.

I was going to jump it again when I noticed that the rubber/plastic surround on the positive terminal in the engine compartment was melting from so much heat. I moved it around a little bit and then started my car and it fired right up.

It is still doing the same thing and I am really concerned that there may be a short somewhere. Any ideas? also once in a while my audio cuts out on my right side. (dont know if that is related).

How much does it normally cost to diagnose electrical issues like the one I have? Has anyone experienced a similar problem?

I have a 2002 X5 3.0 (e53) with 228,000 miles