318 runs rough when warm

Long distance diagnosis for my brother. He has an 89 Ramcharger with 318, throttle body injection. It runs great when cold, but after it warms up for about 5-10 minutes, it gets rough. It feels like it loses power and acts like it is flooded or not getting fire properly. Then it quits, and will restart and run a couple minutes, but very rough. He says it shows code 37, but always has shown that. My first thoughts coil wire, coil, distributor cap/rotor. Any other thoughts before he starts replacing parts?

I had a truck do the same thing and the culprit on mine was the wire from the temperature sending unit was broke in two. The computer wasn't getting the signal that the truck was warm and kept feeding fuel to it like it was cold.
Brad

Coolant Temp sensor can cause that.

yeah that's what I was thinking, one of your sensors is jacked up.