The 2005 model year likely incorporated changes to meet stricter EPA emissions regulations. These could include:
* Updated Catalytic Converter: A more efficient catalytic converter to reduce harmful emissions.
* Refined Engine Management System (ECU): Software updates to optimize fuel delivery and ignition timing for better emissions and potentially slightly improved fuel economy.
* Minor Internal Component Changes: Small changes to internal components like pistons, rings, or valves might have been introduced to enhance reliability or durability, though this isn't always documented publicly.
However, the fundamental engine design (whether a 2.4L naturally aspirated or a turbocharged version) remained largely the same. You wouldn't find a drastically different displacement or fundamental architecture. To know the *exact* differences, you would need to compare the engine specifications from the factory service manuals for both model years.
In short, expect differences primarily related to emissions compliance and subtle refinements, not a complete engine overhaul.
