I need to know how to adjust the idle on a 1993 pontiac bonnieville

As far as I know it doesn't have one, but if it does it will be above the glove box insert

is the vehicle blowing white smoke from the tail pipe - if so that is a very good indication that it needs replacing

Better get this one to a mechanic. Sounds like you blew a head gasket.

Adjust gears for what?

Don't try to adjust the idle speed. Very very bad thing to do. Have your idle air control unit checked. Probably shot, or carbonrd up. Also have your throttle body cleaned.As far as the shifting goes, have the shifter interlock checked. These are both things that are better left to pros, as the diagnosis requires special equipment, and information.

I suggest you check your oil pressure with a manual gauge to know the exact oil pressure. If it reads different then it's the sending unit or the gauge itself that is the problem. Most often it is the sending unit. I hope this helps.

Seems like the prindle switch has to be adjusted, most of the time (on newer vehicle) its done through the scanner.

MAP SENSOR OR FUEL OR AIR FILTER

fuel pump could be overheating and need replaced, if this happens exactly the same each time it seems that is the case, the gasoline in the tank cools the pump through the returned system, alot of people that drive around near empty all the time will burn out their fuel tank quicker because of the pump not being cooled properly, you have spark when the car wont start?

for the idle i would say idling sensor. for out of drive sounds like a trnsmission problem.