Van cuts off randomly while driving

When I first start it in the morning in cranks and runs fine till about 15 to 20 minutes and it cuts off. It cuts off while driving on the highway, low speeds, and even when stopped, it is just random. I pull over put it in park, turn the key off then crank it and restarts and runs fine all day. A couple of times it did not start right back up but after five minutes it did. No engine lights, have all lights and electrical working, put in new battery and iac valve, had new pcm 2 years ago. This never happened until I changed the blower motor resistor, it only worked on high but after I changed it all speeds work but it is very loud on 3 and 4 not sure if this has anything to do with. I put the old resistor back in to see if it would be loud and it was but it was not before I put in the new one.