odd issue with friends Blazer
 

I visited a friends house last night who is a Blazer owner. She has a 98 I believe, and she has a very interesting issue. I've never heard of this happening before, it dies when it's hot outside. The temp gauge still reads normal, it runs fine, but when it's hot and humid outdoors, the truck dies. And it won't start again on it's own for a while, but when it does, it starts right up and runs for a while and then dies after a while. She's replaced a list of items from sensors to the plenum to now the cap and rotor. I read online via a forum search and found someone who made a heatshield for thier ICM and the truck didnt die for about a month and then the posts stopped. Has anyone else ever heard of this issue and now how to fix it? She's starting to exhaust all of her ideas.

Has the ICM been tested? Repeatedly to get it hot, simulating operating conditions?

As far as I know she hasn't done anything to the ICM, but I will run it by her and find out. What I saw in the search was a guy who used an infared thermometer and zapped the bracket of the ICM and it read 177 degrees, mixed with the humid temps over 100 degrees it made the truck stall. She said it's been doing this for a year or two and in the fall and winter, or when it rains there is no problem. It's only in the spring and summer when the temps go up.