Wont start

I checked the gas gauge when my wife said it would not start, it was on empty. I put two gallons of gas in it and it started right up. Problem solved right?
We ran it for a day and parked it for the evening. Next morning it would not start. Fuel pump right? Or perhaps bad gas.
I bought STP fuel treatment and starter fluid. I put the STP in the tank and sprayed the starter fluid into the air intake. After several attempts it started, hooray! Problem solved.
Not hardly, we ran it for about an hour hoping to get the "bad gas" out of the tank. Parked it in the driveway and the following morning it would not start.
After some research on the internet I found several articles that caused me to believe it was a cam shaft positioning sensor. I replaced it and still wont start. I also replaced the cable going from the positive terminal into the computer box. It started and we ran it for several hours afraid to turn it off it did, however stalled and cut out after about an hour and ten minuets of driving it.
I am at a loss and need some professional advice.
Please help!
Thank you,
Daniel