ok, so just to recap, u have the 10% OD, a flowmaster cat-back and a K & N panel filter, correct ?
your next upgrades should be :
an IC fan
custom downtubes to change the angle (with or without cats)
like everyone has said, your SC is making too much heat for the stock intercooler to handle and the EEC is pulling timing because of it.
i just think slapping a 10% OD on an otherwise bone stock SC is really asking for it.
hell, i have full exhaust, ported heads and intake, FMIC, raised top and im only OD'ing my 94 blower 8%. (prolly should be more but we'll see)