I have a 2001 Disco II that keeps failing emissions testing. OBD II codes keep changing. Latest three are 0440, 0734, and 0155. Will new O2 sensors fix this, or is there more going on?

 

How many miles on your truck, when was it last tuned?
0440 Evap, emission controls problem
0734 4th gear incorrect gear ratio
0155 O2 sensor heater control on bank 2, sensor 1.
So how many miles on the truck and what octane gas are you running?
Mike

 

It has 190,000 miles and I use 93 octane.

 

Also, it was tuned recently but may have non-rover plugs