Hey guys,

I drive a R50 2003 68k miles Cooper CVT Auto. I recently noticed the engine rev'ing up under the following (typical) conditions:

- Cruising at steady 70mph@2800rpm (this is normal)
- Foot on the accelerator but steady pressure
- Suddenly the rev rises to 3500rpm (almost feels like it's dropped a gear to 5th)
- If I accerelate, then the rev goes back down to 2800rpm@70mph
- The same problem happens if I drive in tiptronic mode in 6th gear so the LCD display still shows 6th gear but the rev will go up randomly...

Basically, it feels as if the car has dropped a gear (like driving a manual car) to 5th when I am in top gear driving at a steady speed. This happens in any high speeds on the motorway at 80mph etc...

Question for you guys - do you think this is...

- MAF gone bad?
- O2 sensor/s gone bad?
- ECU gone bad?

Is there anything I can do to isolate the problem (e.g. drive with MAF cable pulled out), or 'reset' the ECU etc.?

Any advice will be greatly appreciated!

This problem has plagued my 2006 R52 CVT ever since we got it a couple of years ago. Seems like the vehicle likes to rev high, waits until about 55 mph to get to 6th gear, and when I switch to tiptronic, it shows gear 6 on the lcd, but the car sounds like it's downshifted to 5th. As soon as I put it back to D, it upshifts back. Hope you get an answer.