MPG Improvement with ECM?

[mc190skier]

Anyone know of any ECM modifications or aftermarket products that can improve gas mileage? I know the Impala SS has a feature that lets it run on 4 cylinders instead of 8 when the extra power is not needed, and Cadillac Northstar V8 will automatically 'cool' cylinders by shutting them off if coolant is lost from the motor.

Appreciate any info.
:thx

[ieatglue]

Do you have a V8 or the I6? I've heard that many people report an increase in mileage with the PCMforless tune :yes: