Ditch the Platinum plugs for starters, that motor does not work well with them. Put some W9DCO Bosch in it.... the bad news... they won't fix it either. But it will not run correctly even after you fix your other problem. My first thoughts are vacuum/false air leaks in the intake system. Injector seals and idle air hoses are common leaks with the miles on your car. I suggest this because of the back fire you hear. Dripping injectors are a possible cause too. They will cause a start/die/restart complaint. A lose of fuel pressure will cause an extended cranking condition and affect a hot engine restart most. There could be other causes but I think you will find your problem in one or both of these areas.