Update on L-98 Pinging

[The Thibodeaus]

I talked to Performance Resource today and they have reprogrammed a portion
of the chip where I was having a severe ping with my 90 Vette.  They stated
that they pulled out 3 degrees of advance and richened the mixture.  My
question is, this is a low speed problem, i.e., pulling at 1/3 to /12
throttle from 25 mph to 35 mph.  If the engine is closed loop, how can you
alter the mixture so it is richer.  Is there a table for desired AF ratio
to match the BLM numbers?  They also want me to move my MAT sensor from
where I re-located it (intake tubing) to the stock location in the TPI
plenum.  This will signal the ECM that the air is warmer.  Wouldn't this
tend to lean out the mixture?  I am not sure what they are trying to
accomplish with these changes as they don't make much sense to me.  Does
anyone see the logic in these changes?

Bob T