That is a good artical ^^^^. I have one that i did that is not as good as the one above but you can never have too much information if you plan on doing it yourself. Look HERE

I had the EXACT same problem with my starter and cleaning the battery did not do the trick. The starter was the problem. The hardest part is getting the starter out. Replacing the contacts is not hard at all.

Hope this helps!

99 Limited 4Runner 4WD
ARB front Bumper Kennesaw rear bumper
WARN 9500 Winch
Hella 4000s