I have a 98 Blazer. My problem is on cool days runs great but when the temp gets above 70 when you are at a stop it will begin to idle rough and shut off. I pulled the codes and the only thing I got was the O2 sensor after the CAT. I changed that but I am still getting the same thing. It has a new distributor, cap plugs, wires, ignition coil and fuel pressure regulator. I was wondering if maybe it is the TPS causing this? Any ideas will be greatly appreciated.

 

This sounds like a heat soak electrical failure. My first thought would be the coil pack, but you don't have one. I had an old Dodge once that I converted to electronic ignition. It did the same thing. It would run fine on a cool day but when it warmed up, it would sputter, run rough and then die. It turned out to the the brain box had an internal fault. When it warmed up, the crack in the circuit would expand and open.
I don't think it's your throttle position sensor, but I would check the MAF sensor in the air intake. It could be your computer but I'd check the cheap and simple stuff first. Look for something electrical that gets hot. On my old Dodge, I popped the hood to the safety catch and it ran fine with air flowing over the unit to cool it.