Something similar happened in my brothers 98 Blazer. Unpleasent clicking noises when trying to start (about 2 a second), he thought it was the battery, so he replaced it and the problem went away. A couple days later, problem returned. Turns out the alternator was busted and all replacing the battery did was allow the car to drain it until it was dead. Don't know if this helps you, but I'd thought I'd put it out there.

John

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1995 E320 119,000 miles