Q: Intermittent starting problem, why will car not start consistently? on 2000 Nissan Altima

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
Problem began with "traditional" battery clamp on positive battery terminal. Replaced it before and starting problem solved. Tightened screws connecting the 2 cables which connect to the clamp and problem solved temporarily, but when car stopped, it is as if there were no power in the battery or no battery at all. Unable to jump start the car from another car. Power is good in the battery. Replaced "traditional" battery clamp to one appropriate for Nissan Altima which allows the 2 cables to be fastened to the clamp by a separate bolt. Starting problem still exists. Sometimes the car will start and run, but often it is as if there is no power. Cleaned metal connectors with interlock with a wire brush on a drill and the positive battery terminal - still will not start consistently.
(2) Answers
(9) Comments
Possible starter is just old & tired... can you check for voltage on the small wire at the starter while helper turns key to start?... If voltage is present... starter is most likely the trouble.!!
If it were a bad starter I would always have power to my dash and the internal courtesy lights. I intermittently lose all power: no power to the dash, no lights, radio, et al. Shut the door, come back and all is well, except when I turn the key to engage the starter I again lose all power (no power to dash, et al); other times it will start right up.
While it is acting up... check main power supply wire with a volt meter... find out where the voltage stops! Wire may be from the positive battery post or the starter connection...
Next time it 'acts up' , see if the headlights work , if they do , leave them on (have someone watch , if needed) and try to start the car. See what the headlights do , if they go off as soon as you turn the key , do what was suggested by pushrod and find your bad connection.Or go somewhere else for free crappy advice.Do you have a voltmeter?
Yes, I have a voltmeter. Lights, dash lights, radio, et al stay on until the key is switched to the start position to engage the starter. Sometimes switching the key to the "On" position causes power to cease also. I'm thinking it's a very bad battery cable at this point, but the connector at the battery is clean and the clamp to positive post is new and clean.
Problem fixed! I was so fixated on the problems surrounding the positive battery cable that I presumed the problem was with that cable. The negative cable looked fine and was tight on the post. On a whim I replaced the clamp and cleaned the post. Problem solved.