a while back my truck started acting crazy, its a 1992 f-150 straight 6 efi with 5 spd trans, well it starts and you have to rev it for a while in order for it to stay on, if you don't it will cut off especially if you put it in gear and try to go.....well i got a new car two weeks ago and ive been driving it, this morning i got into the truck and drove it to work and the damned thing never got to anywhere in the normal operating temp zone....its stayed in the cold zone the whole 35 miles, i figured it had to do with me having the heater blowing on full the whole way here, but when i went to lunch i drove it for about 45 minutes, with the heat off and it barely got to the lowest "normal" reading on the gauge, could it be as simple as the thermostat sticking open?