system too lean or too rich.. the only thing i can think is that ,aybe because i run a high fuel PSI (too high maybe), and it has ONLY happend in severe heat when i first start up tha car and drive a little and it stalls... i think it have to do with a slightly off vavle adjustment, and too much gas.. bogging it down, because off nitrous some times i bog off the line ie too much gas.... adn once the car warms up even on a hot day it is always fine... i hate to do another adjustment becasue the car runs so good now (engine driving once warm, and very quiet, and also good smooth idle) so i may just leave it, it has only happend twice...