My 94 stock Dodge (115,000 miles)sometimes will die on a hot day when I'm pulling a hill and the tranny downshifts and the motor revs up. Shortly after that happens the motor starts to miss then dies. After pulling to the side of the road and waiting a couple minutes it always starts right up and acts like nothing happened. I'm wondering if the overflow valve is sticking open or a check valve in the lift pump is sticking open. I've replaced fuel filter, cleaned the screen in the heater and the screen in the fuel tank pickup. Any ideas???