Could it be that you have bad fuel, causing one then both [new] lambda sensors to fail ?

I would first put a multimeter across the connectors to each Lambda sensor to confirm that the voltage is actually indicating a poor mixture.

In the case of two flashes / poor mixture error code, the manual i have indicates to check as follows:

1. Check proper operation of fuel pump, fuel level, electrical supply to fuel pumps

2. check ignition system, poer module, coils, high voltage wire, distributor, spark plugs

3.check fuel pressure regulators

4. check exhaust system, air infiltrations before the lambda probe

5. Check electric and vacum connections to the intake plenum, of the absolute air pressure sensor

6. Check lambda probe wiring


I hope this is of some help, and that someone else will chime in and help.

Please post the feedback, its always much appreciated.

Regards