91 4Runner

I go out to the truck on Saturday, and for no reason it won't crank over (like the battery is dead.... No click, spits CD out of player and resets clock and cd settings) So I think "OK I must have left something on" Check everything, and nothing was left on... So I charge the battery and try again.... Nothing no click nothing.... So I boost it with another battery - starts right up... So I think OK I need a battery, so I buy an Optima Red top. I think OK this will fix it. Install the battery and nothing, so I boost it and it fires right up.... So now I'm at a loss, I'm thinking maybe starter? I don't know.... The charging system works (guage reads about 16 volt, and I can remove the positive terminal while it's running and it continues to do so..... If it is the starter will a 4cyl starter fit a 6cyl? Any ideas? Need help quick

celica

Try you battery terminal connections. If they are dirty, corroded it will do the same thing, when you jump it you have a clean connection from the jumper cables. Cleant the cables, post and give it a try.

MAtt