Ford escort wagon 1995

I SMELL OF GAS IN MY CAR BUT CAN NOT FIND A LEAK,THE SPEEDOMETER FLUCTUATES, AND MY CAR WILL CUT OFF IF MY FOOT IS NOT CONTINUOUSLY ON THE GAS PEDAL

When do you smell it (the most?) Does it smell stronger under the hood the rear of the car etc.? How long has it done it? When is it worse (right after driving, after filling the tank, after parking on a hot day???

I only smell it when my foot is on the gas. thanks for your reply