I have a 92 4.3 that I have have been trying to tune. The data logs I read say that my blm is 128 while reading 12.5 afr on my wideband. During highway cruising my narrow and drops mV and will raise the blm all the way to 160. The wideband will read all the way down to 9.5 afr at a cruise. Will adjusting my fuel tables even help if I am running rich but my narrow band thinks it is lean?