[Joes 5.0]

Sounds like a bad connection or a bad armature in youre starter. If it still clicks the connections are good, if not look at the selnoid or connection leading to the starter

 

[Joes 5.0]

I'd say most likely its not your battery, because when youre car is off nothing is charging the battery, and if it goes from nothing to starting the car up, well, it just doesnt sound like a battery problem unless. However, stuff can get pricey when you assume things like that, so it never hurts to get the battery checked out. But i'd say get a DVOM and do a voltage drop on your starting circuit. I cant think of what it is called, but there is a switch in the back of your car, (if its a hatchback) right by the hatch lock. Pull that out and that will stop the car from starting and sending fuel so you dont flood your engine. Dont quote me on this but I think the only things in this circuit is the S terminal on the starter, nuetral saftery switch (if its manual) ignition switch, selnoid, and battery cables and ground. Test all these and see where you are getting high voltage at, thats where your problem is going to be at. Good luck