1991 Chevy Lumina Car stalls once warmed up

Jump the diagnostic center and post the codes you get. We'll start there.

Ran the test you had mentioned and it kept flashing 1 & then a 2 meaning 12. Did this several times. I was told by the manager @ Auto Zone that means no problem. Well, there is a problem but it's showing nothing. I did run the car for a little bit today & it hesitated like it wanted to stall but only when I put it in reverse I gave it a little gas & it kept running. I did see drops of antifreeze where the car was when I put it in reverse. I work on cars and know a little but this really has me puzzled. Any suggestions or comments are greatly appreicated.
Thanks for your post appreicated it!

Definately find the location of the leak. As for the hesitation, im sure you know enough to do a full intake cleaning along with both tps and iac. Lums are also known for the sticky tcc. Drain a pint of tranny fluid out and put a pint of seafoam transtune in. Atleast that will eliminate a few typical culprits.

I had this problem, it was a bad injector. They are electrical, when the car got warm the injector electrical heated up and esentially "told" all the others not to work. Replaced the bad injector and fixdd it.