I can't place what minestrone soup (good or bad) or a chemically tomato sauce smells like, but if this is a new smell I certainly would not be using that heater till fixed by a Heating and A/C contractor (your Search the List category).
Could be burning insulation or switch/control unit, burning wall, burning flooring, overheated metal (only thing I can think of offhand that smells a bit like tomato sauce) or a dead animal being roasted behind it. Either way, sounds like something could a toasting - and if you use it more you might find yourself with toasted house, so leave turned off until fixed.
