1995 Ford F150 Starving for fuel/ bad gas smell

I have a 1995 F 150 4.9cyl that I am at my wits end with. I bought it used about 2 months ago for work and for the last month it has not been working well. The front fuel pump is out of it and I have been using th rear tank, but now truck will not idle well. Will bog down upon acceleration. It will hiccup while driving down the road. Somtimes I will switch the tank from the rear to the front, and then back again to give things a little jump start and it works untill I get to the next stop sign. Now it will no longer run with the switch in either front or rear possiotion. The rear pump was tested for preasure and I was tod it was fine. New fuel filter. New O2 sensor becasue when hooked up it coded that it was reading rich and the computer was leaning out the mix. After installed the new O2 it reada the same reading. Help, 2 garages and alot of frustration and money later I still have no effin idea what is going on with this truck. When it runs, it runs strong.

At my wits end,

Nick.