High revs while driving??

[anubisx5]

If anyone could offer some idea to whats happening I would really appreciate it.
I have a 02 X5 with 3.0 L and about 95K miles on board. A few days ago while driving I noticed the engine to be working (noise and vibration) much harder than it should under normal driving condition. Normally the engine is smooth and silent. It feels like too much fuel is being sent to the engine for the speed. The RPM on the tach seem to be normal and gas mileage has decreased over the past few days.

The only SES code came up are for the pre cat O2 sensors, they have been changed but has not helped the over reving that is happening. I don't think its an engine mount or a tune up issue.

ANY THOUGHTS??