I'd think cleaning the MAF is a good place to start, use a good cleaner designed for MAF's and be gentle.
( The MAF and IAT sensors are combined on this engine )
the 171 and 174 are kinda confobulated, one says O2 detects too rich, while the other says too lean. WTF ?
I think I'd also want to have a look at the throttle body and clean it up also, and a new O ring.