How to troubleshoot, repair & maintain toyotas 4 runner motor 3.0 1992 thanks

For what specifically. The question you asked would involve copying verbaitum the entire engine section of the 4runner factory service manual to answer.

... and I have all that right here at my fingertips, there's no way in hell I'm going to look up all that!!
As I tell my wife, I need specifics, dear.
But seriously...

'92 4Runners V6 3.slow Liters are not as common as Honda's around here, so you won't find any FAQ or stickys on them.
If you have some specific questions, by all means bring them on, right here on this thread.