I have a 91 f250 302 fi. I am having problems when it gets really warmed up. It starts back firing, when you take off from a dead stop. You have to barely push the gas to get it going. Sometimes you have to let it cool down for about 30 min and it is OK again for awhile. When it is cold it does have a slight back fire when you take off. I have replace the tps, coil, plugs, plugs wires, temp sensor, fuel filter, the whole distributor and block off the egr valve. The cats have been taken out. It has very little power pulling a trailer and gets horrible gas mileage. The plugs are all the white side (lean). Fuel pump show 30 pounds at an idle. I understand there are suppose to be three fuel pumps on a dual tank set up. I cannot find the third fuel pump any where on the fuel line. So I am guessing it is running only on the tank fuel pump.