[ChevyTech]

Code 32 is usually set because the EGR does not work at all. Worry about this last.

The code 34 (MAP code) low voltage that would be caused by high vacuum (that the ECM determined is suspect), which could be a loss of ground issue. A stuck open EGR would cause a low vacuum / high voltage code which is the oposite of what you have.

Anytime this system sets a rich code the first thing you should test is the coolant temperature sensor that the ECM uses because it is one of the criteria used by the ECM to determine how much fuel to inject. It screws into the intake manifold by the Thermostat. If you have an ohm meter I can give you the specs.

This group of codes does not look right to me. I would clear all the codes, drive the truck, and see what codes get set again.