Can't find solution to my problem

I have a 93' mx3 that has been in to the dealer four times and they still can't find out why it is having problems. Prob #1 is that when the fuel tank reaches just below half and you go around a right hand corner the engine dies...not a half a block later but mid turn...never on a left turn only a right turn. Prob #2 is that when the temp outside reaches over 100 the car loses power and surges after 10 or 20 min of driving. It doesn't die ...it just has no power. If you turn it off for like 1 min or so it will start up fine then drive okay for a short time. When the temp outside is 112 it is even worse. It doesnt do it when the temp is cooler.