2001 Audi A8L with 60,000mi. Check engine light came on intermittently, now on all the time. Fault code indicates lean fuel condition banks 1 and 2. Tested all 4 oxygen sensors and they are putting out within specs. Mass air sensor also within specs for output. Next step was to check fuel pressure. Suspected fuel filter had never been changed. Put new filter in and fault remains. Car runs great. Any suggestions to get rid of the fault light?
RG
RG