car is hard to start first thing in the morning

I have a 97 ford explorer 4.0 sohc. It is hard to start first thing in the morning. My driveway has a slant to it. If the car is pulled into the driveway, it does not want to start the next morning, but if it is backed in the driveway it starts up the next morning with no problem. Have had the fuel filter & the fuel pump changed. It still has the problem & now that the pump has been changed, the gas gauge does not work.