1998 chevy metro. starts intermittently. battery is good. when it’s hooked up to another battery it starts on cables. Sometimes it just makes a clicking sound. sometimes a click then turns over. What is causing this unreliable starting behavior?
How do you know the battery is good? Have you cleaned and properly reattached both ends of each battery cable?
Right! Disconnect the battery cables, and clean the terminals and battery posts with a wire brush, smear Vaseline (or, silicon grease) on the terminals and battery posts, and reattach the cables
I suggest having the battery tested, and checking the cable connections at BOTH ends. They must be clean and tight.
Sounds like a battery problem, though.
Have the charging system tested while you’re at it. Most parts stores will test these components free.