1990 Chevy Lumina car dies while turning

Lots of things can make it stall like that, lums are known for it. I would start by checking all vacuum lines, then do a complete upper intake cleaning. Make sure you clean the tps and iac while you're at it. If this doesnt cure it, go onto cleaning your egr valve then drain a pint of tranny fluid out, add a pint of seafoam transtune. This will lube the tcc and keep it from sticking in most cases "if that is whats causing it to stall". Things like this are hard to find whats causing the issue, you have to do one thing at a time. Be patient, its worth it once its fixed.