Is the engine on a 2004 Ford Focus vetec 2.0 liter interference engine?

The 2004 Ford Focus did *not* use a VTEC engine. VTEC (Variable Valve Timing and lift Electronic Control) is a Honda technology. Ford used their own variable valve timing systems in some engines, but not VTEC.

Furthermore, whether a 2.0L Ford Focus engine from that year is interference or non-interference depends on the *specific* engine code. You'd need to find the engine code (usually stamped on the engine block) to determine this definitively. A quick online search for 2004 Ford Focus 2.0L engine codes and interference/non-interference status might help.