Chrysler has introduced iDFSO, Interactive Decel Fuel Shut-Off, software that cuts fuel to the engine while decelerating, to increase gas mileage. The amount of fuel shutoff is increased with certain engine speeds. This system increases both city and highway gas mileage, and lights a Fuel Saver indicator light when active.

The system is being phased in on 2009 model year cars and will be on numerous 2010 vehicles. For 2009:
  • CVT and manual Caliber, Compass, and Patriot Limited
  • Wrangler (with manual transmission only)
  • Charger and 300 (5-speed automatic)
  • Challenger (manual and 5-speed automatic)
  • Nitro 4x4 (4.0 / automatic)

For 2010, the system will be added to:
  • 4.0 liter minivans
  • Wrangler  automatic
  • Grand Cherokee V6
  • Nitro, Liberty, Dakota, and Ram 1500 with V6 and automatic
  • Dakota V8 automatic
  • Ram 1500 V8 automatic

oh20 noted: the fuel saver indicator light will be added to the minivans, LX cars, Journey, Nitro 4x4, all Jeep 4x4s (except Patriot/Compass), and Ram 1500, with select engines, for the 2010 model year.  It will advise people when they have reached the economy target zone and fuel-saver mode target range.