MY TRUCK HAS 11K ON IT AND IT IS GETTING A LEAN CONDITION ON BANK 1 AND 2. THIS TRUCK HAS A REBUILT TITLE. THE TRUCK WAS HIT ON THE PASSENGER SIDE FRONT. THE AIR BOX WAS REPLACED A 4.8L ENGINE PART. I AM NOT SURE WHAT ELSE WAS REPLACED. GM TSB CALLS FOR A O-RING AT THE MASTER NEEDS REPLACED BUT THE TECH REMOVED THE VAC HOSE AND THE CONDITION RETURNED. I AM LEFT WITH POSSIBLE O2 SENSORS. THE GM TECH HAS GIVEN UP. CAN ANYONE HELP.
Think about turning off your caps lock.
Why was the incorrect air box used? If both banks are lean, I doubt if replacing O2 sensors will fix the problem because (a) the likelihood that both o2 sensors are bad is not very great, and (b) the o2 sensors are reporting the problem, not causing the problem.
Was the air flow sensor from the smaller engine used as well? If the incorrect air flow sensor was used, it is possible that it is sending the incorrect values to the ECM and so the engine runs lean. Other possibilities are damaged wiring, particularly the wiring between the air flow sensor and the ECM.
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