1995 Chevy Silverado 95 Chevy k1500 idles rich and stalls w

When mixtures get off the first thing I think of is the O2 sensor. They don't last forever and cheap ones can last a year or less. If an O2 sensor goes bad around the same time that a MAP sensor goes bad well thats a real bad combination.

So along with the IAC the MAP and O2 sensor control the mixture via the computer and input from the TPS. The TPS is another good sensor that can go bad and cause symptoms similar to what you have.
If you can find it in the autoparts store there is a tool made for testing sensors. It will test all kinds of sensors and I use it quite a bit when I get a troublesome rig in. You should also have some computer codes thrown that a scanner could probably reveal and shed some light as to what your computer thinks its sensors are telling it.