[word=fuel] □
[word=fuel] □ □
[word=fuel] []
" Hybrid vehicles are the heart of our plan for the future , " said General Motors spokesman Mike Morrissey , noting that up until 2000 , hybrid vehicles " had limited appeal because customers were forced to chose between fuel economy and functionality . Proposed approaches for CVT control systems should address the critical operational issues of fuel economy and impact on vehicle driving characteristics . Whichever engine Ford chooses for the 2009 Mustang be sure it will definately use DOD technology ( Displacement on Demand ) where as the engine can shut off 4 of the 8 cylinders to improve fuel economy and boost overall horsepower past the 300 mark . These tests showed that a catalyst usually made " almost no change in either fuel economy or exhaust soot levels .