89 firebird turns off

i have an 89 firebird with a 5.0 and a 700r4 tranny. yesterday i was driving and was at a red light my car just turned off i felt the engine hesitate then die. it started right up but its done it before too any ideas.i know for sure i have to replace the heater core cus i see anti-freeze in the pass floor area so i check and fill it for now till i can replace it also the vats is bypassed incase that has something to do with it any help would be appreciated
thanks
Adam A.

Not clear on the death of te engine at the light, did it just "shut off" abruptly or die a slow choking death?

slow death cus i made in the center of the intersection lol thank god it started right up

Well, putting one and one together based on your post, the leaking core may be part of the problem. These cars run hot by design for emissions. At the same time, the ignition system gets very flakey with extreme heat. I would suspect that the ignition coil or ignition control module got too hot and caused the stall. I would definately eliminate what you know is a problem before sloothing around further. May I also suggest while the cooling system is drained to repair the core, replace the coolant temp sensor, fan switch, thermostat, radiator cap as well as inspect/replace any neccessary hoses, cheap insurance you know.

Thanks i ordered the heater core i should get it 2moro but i cant put it in till my day off which is in a few days. I'll try what u suggested and see what happens. Thanks again