1993 Ford E-Series Van wont start on hot days

I have a motor home on a e-350 chassis with a 7.5 liter automatic. I have had the fuel pump in the tank replaced as well as the fuel filter 500 miles ago in AZ. The RV was surging and died on the freeway. The tech. Could not reproduce the problem after it cooled down over night, later they decided it was the pump. Once in CA the rv died after turning it off for an hour, it cranked but would not start. Again after it cooled down the next morning it started. Getting home to WA. On our way the rv started to lose power going over the mountains, felling like the Transmission was slipping, it would lose MPH as I climbed the hills, it would down shift and go slower, once it shiffted into first it would not go over 15MPH. Now there is also a rattle noise comming from the tranny right before it shifts, seems to run on flat level surfaces. Since being home (after limping from Cresent City CA) it has sat for two days, I went to start it and it started, but died real quick, and now it wont start (it is also over 100 deg. At this time here) Could this be a fuel Regelator problem, our do I have two seperate issues?