The loose connection is probably at the battery cable ground on the engine. It is definitely a connection issue, and is usually either the spade terminal on the fuse link (dirty or loose connection), or at the ground on the engine. If you tried to make the connections look better by eliminating any washers, or painting the block and putting the cable right against the paint, then this will likely be it. On my car, the addition of a star washer under the cable end on the block fixed all. Every time I checked my connections, I got good readings (no resistance), but it would constantly pull the overcharge/normal trick. In frustration, I pulled the ground for cleaning of the interface between it and the engine, and said, "What the hell, I will put the washer on- I have one now." I immediately cured the problem. Apparently, the connection was excellent every time I checked, and lousy every time I turned my back.
