[undy]

My first thought would be fuel system heat soak (vapor lock), all other things in proper working order. After you make a 1/4 mile run with an already warm motor you build up a lot of heat. After the pass there's a lot of stored energy (heat) still remaining in the engine, coolant system and surrounding under hood areas. With the hood closed (you didn't mention you opened it so I'll assume you didn't) your under hood temps go through the roof, causing the fuel to boil in the lines. Your injectors are set for a certain pulse duration. That pulse duration assumes that the fuel is in liquid form. If your fuel is a gas/liquid combo you could be starving the injectors, hence the extreme stumble and inability to keep it running. Try insulating your fuel lines better with the reflective foil coated insulation sleeving available through any performance parts outlets. Or .... try opening your hood always between runs..

Other things it could be are. leaking injector(s), ignition failing under heat (MSD?), heat related F/I control module problems etc..

Dave