There were many diffwerent styles or series of the Jaguar XJ. The smallest engine was 2.8 liter. The largest was 4.2 liter. The "Series II had a 5.3 liter engine.
The 2013 Jaguar XJ has a V6 engine.
The 2012 Jaguar XJ has a V8 engine.
The 2009 Jaguar XJ has a V8 engine.
The 2011 Jaguar XJ has a V8 engine.
The 2014 Jaguar XJ has a V6 engine.
The 2014 Jaguar XJ has a 3.0 L base engine size.
The 2009 Jaguar XJ has a 4.2 L base engine size.
The 2012 Jaguar XJ has a 5.0 L base engine size.
The 2011 Jaguar XJ has a 5.0 L base engine size.
The 2013 Jaguar XJ has a 3.0 L base engine size.
The 2009 Jaguar XJ's engine produces 300 hp @ 6000 rpm.
The 2013 Jaguar XJ's engine produces 340 hp @ 6500 rpm.