1988 318/5.2 runs rough and stalls when hot

Truck in question has 175k, is the TBI version (fuel injected carburetor design), has had the plugs cap and rotor replaced fairly recently.

When cold, it starts and runs normally. As it warms (after around 20 miles) it starts running rough, then after getting warmer/full operating temp, it will stall at stop signs and runs very rich - so rich you can smell the unburned fuel. At this point it is also difficult to start and requires adding some gas pedal.

I am thinking a vacuum issue, or something that is not allowing it to transition from the warm up cycle to normal cycle.

Any thoughts or suggestions would be appreciated.

Check for good ignition spark during stall condition w/spare spark plug.
My young'un had the same problem on a camaro...bad ignition coil.