We just finish converting our 1993 Ford F-350 W/ 7.3 to WVO. This year has a lift pump as well as the injector pump. We ran it to NYC (250 Miles) on WVO with great success, pleny of power, good milage. Oil Temps for 40 gallon tank ran around 160. On the trip home we had problems pulling hills, felt fuel starved on WVO. As it cooled down in the eve and the temp dropped about 10 degrees the problem improved noticably. Pulled the filter, no problems, switched to diesel, ran fine. The oil temp on the way home with 1/2 tank was closer to 195. (we switched to a 195 thermostat and have insulated the tank in prep for winter operation and warm up). We thought the problem maybe caused by the diaphram in the lift pump not handling the hotter oil well. Wondered if anyone had run into this. We bought the Greasecar system if that makes any difference. Anyone hear of this? Are we running the oil too hot?