Mazda CX-7 2011 Problems

Straight back to your dealer is where. But before you do get your facts straight and run a fuel consumption test so you know exactly what the consumption is. Now, the specs you quote are I'm guessing the official figures, if they are they not real life figures, but the results of a laboratory test done under strict conditions. You won't necessarily get the same consumption, but you should be able to get somewhere close. Based on the figures you have supplied you're not, so you have grounds to complain and ask the dealer to check the car over, even run a consumption test himself.
 

I would rule out the CX-7 on the basis of poor fuel consumption, the performance of the iX35 petrol version is a little lacking, the Tucson is a better car, but I would suggest the X-Trail is probably your best bet.

Sludge build-up is a turbocharger killer, but sludge won't build up if the car is regularly serviced and the oil is changed so it's always fresh. The problem is usually only with cars that haven't been serviced. Other seven-seaters you could look at are the Kia Sorrento, Hyundai Santa Fe, or Toyota Kluger.

If the car still has drive in the forward gears, but refuses to drive in reverse, it’s a reasonable bet that there’s wear or damage to the transmission’s intrinsic bits that select or control reverse gear. If the transmission was simply low on fluid or had a bad pump or torque converter, it wouldn’t go anywhere in either direction.

A transmission specialist will probably have seen this problem before and will be able to advise of the extent of the damage. Either way, don’t drive the car any farther as you may do more damage.