I'm wondering where I find my I.C Module on a 99 Blazer 4.3? I was told under the distributor?
is it hard to change is the other question?

 

The ICM (ignition control module) is mounted to the same bracket as the coil. The bracket mounts to the lower intake manifold right near the distributor. It will have a heat sink attached to it.

You simply unbolt it. Most autoparts stores can test this to confirm that it is the source of your issue. I assume you have an issue that you are attributing to your ICM... Remember to pick up some thermal paste to improve the thermal conduction between the ICM and it's heatsink when you put it back together. New ICM's should come with some thermal paste.