Codes say 'lean' bank 1 & 2 o2 sensoe
My 99 Yukon slt 5.7 Vortec has those codes and the CEL comes on periodically, usually after i've driven for 20+ mins but never stays on. Today, it cut off twice while driving almost as if it were out of gas, it did it last month once and I cleaned the MAF, and hasnt done it agai until today....Where are the bank 1 & bank 2 o2 sensors? And when u say after or before the CC does that mean comming from the tailpipe or 'after' as if comming from the front of the truck? Secondly, are all the 02 sensors on the truck the same or are they different for each bank? BTW, the codes are saying p0131 and p0171, when i removed the MAf it appeared blackened but i dont know if it should be that way or not...Thanks in advance guys