Bogging down, stalling at low rpm

[Telcombill]

I've got a '94 GMC, 5L, with TBI
When cruising thru a school zone, or otherwise doing 15 to 20 mph, she boggs down, then catches up.
Sometimes, while stopped at a light, she will stall. I replaced the fuel pump (in the gas tank), and replaced the two injectors, and rebuilt the fuel pressure regulator. Now it happens, less frequently, but, not fixed yet. ? ?

 

[Schurkey]

Connect a scan tool.

I'd be looking at TPS, IAC, MAP, Coolant temperature, and anything else in the data stream that looked suspicious.