Click here to write a Letter to the Editor. img src="http://www.ttnews.com/images/printeditiontag_new.gif" width=120 align=right>LAS VEGAS — Engine maker Caterpillar Inc. said it is subsidizing the cost of ultra-low-sulfur diesel to customers testing its 2007 engines and delivering it directly because the fuel is scarce and costs much more than regular fuel.