After jacking with this engine for some time I think I finally hit upon the source of all the lean codes and misfires. I believe the front exhaust manifold is leaking. I hear this metallic sound from time to time when driving along side of a wall. With the hood up and reving the engine, sometimes I hear the sound at the front left side of the engine - down where the exhaust manifold is. If the leak is upstream of the O2 sensors the extra air will upset the mixture. It will say lean so the EEC will adapt throwing the other sensor off. I see from some past posts that a few owners had to replace theirs. Who all had this problem?
