PO174 system lean bank 2
fuel trimming crazy before it finally faults. This is one
possible way to get the "too lean" code, because
there's no difference between lean output and
brain-dead.
If you force it open loop and clear the trims, and
it runs better then mis-trimming is likely. Ditto if
you can see O2s switching or high right after a
good high-load drive, but then get lazy and quit
as you sit and idle.


