Have never changed an evaporator before. Can anyone tell me steps and difficutlies in this procedure? I have done minor work on A/C systems in the past. Wondering how diificult it is.............

It's no picnic, but it's easier on a GM wrong-wheel-drive body than on RWD vehicles. You need to evacuate the system, remove a ton of ductwork under the dash, remove lines from behind the engine, and exchange the coil. Reconnect, evacuate, oil, and charge the system.

This link should help:

http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/0e/d6/ff/0900823d800ed6ff.jsp

...Unless it's a 3.4 DOHC; then you'll have to take the upper intake manifold off to access the refrigerant lines.