I used my HP Tuners as a scan tool on my 96 LT1 in an Impala SS. The "Advance" as read by the tool sits at -12 deg at idle, then goes down to -35 deg if I rev it (no load) to about 2k RPM. I'm interpreting the negative numbers as meaning there is a lot of spark retard. Why is it pulling so much spark? Shouldn't there be more advance with more RPM?
Also, the short term fuel trims show very different #s for bank 1 and bank 2. Bank 2 shows a higher numerical % trim. Does this indicate the PCM is fueling bank 2 more, possibly because I have failing injector(s) on that side? Which is bank 2, passenger or driver?
Or could I have fouled O2s on one side (dual exhaust, pre and post cat O2 equipped) which is telling the pcm that the bank is running too rich when in fact it is fine?