I'm not sure if this is detonation, lifters, or a pulley making this noise.

It doesnt make the noise at high RPM driving, or driving uphill. It only does it at low rpms. One of my idler pulleys was making a similar noise 6 months ago so it could be that.
I'm getting code 32, so possibly it could be detonation from EGR failure. BUT, I've had code 32 for a few months now with no prior pinging.
Any ideas?
The car does not burn oil or smoke and never sees past 5kRPMs

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91 Formula 1LE 1 of 46
305 TPI 5speed
1LE/G92/WS6

Paxton SN92 supercharger(SN93 upgrade), Ford SVO 24#injectors, Crane AFPR,SLP airfoil, ported/polished plenum, March alt. pulley,Crane Gold 1.6rrs,MSD coil,MSD6AL (5200rpm limit),Holley 9mm wires,Ac delco R43ts plugs,custom chip,Bosch O2sensor,SLP 1 5/8" headers,SLP catback,shortened shifter,3:73s w/Auburn posi,170* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.