Rays Vet

Newbie here>From my understanding in atap 15.9 is what the pcm will try to accomplish.I've always thought 14.7 was the goal as far as stoich was concerned?When I last installed(tried 4 times)atap it was saying hardware does not match what was installed.I deleted and started all over on installation but still
get the same message.It is working properly(I think) giving real time info but some of the info such as 25% fuel trim(lean?) but o2
averages are .690 to .790(rich) not in wot.Wot appears to be okay at.890 to .930(I know it is not an accurate way measuring)
but the 25%lean trim I have used the translator to richen it up going from 1notch to 2 notch to 3 but no effect on lowering the lean trim.I might add going to notch 1(richening) and even better notch2(richening) does smooth out a lean condition I could feel at idle.Anyway is the pcm trying to reach the commanded 15.9afr which is giving me the 25% fuel trim???Oddly enough with the o2
readings of .690 to .790 why would I still have 25% fuel trim???
I know it's a long post , but I would appreciate any info


__________________