1989 G20 van with a 5.7l fuel injected throttle body. Having problems with stalling when hot at slow speed just after lightly tapping gas pedal and spudering when driving slow,lick its to rich or something like that

What's the fuel pressure at idle? Should be around 10 PSI. When was it last tuned up (plugs, wires, cap, rotor, fuel filter, air filter)?

Find out why the check engine light is coming on.

http://www.troublecodes.net/GM/ this page will explain how to retrieve codes from your van. Its quite simple and any conductor will work. It doesn't necessarily have to be a paper clip.