1990 Chevy Suburban Hesitation/stalling when driving in cit

I am having an issue with my 1990 suburban where when driving in the city or slower speeds I am getting hesitation/chugging and sometimes stalling. However when going on the highway there is no issue. There is no overheating and it isn't throwing any codes.

*update*

So I did the Below suggestion and it didn't really help much. It did seem to run better however still wants to stall when it is warm and driving stop and go. We also replaced the thermostat on it fearing it was over heating and didn't know it. Any other suggestions? Possibly a plugged fuel filter? A friend suggested it may be vapor lock. Though from everything I read with a fuel injected truck it wasn't an issue.