See what your O2 millivolts are when the TC locks up. See if it drops off really low momentarily. Sluggish O2 sensor may be letting it lean out much(sluggish meaning it doesn't "bounce" as often as it should when in closed loop), a kink in the line or a partially plugged fuel filter may be a problem also. TC shouldn't be locked under WOT and the ECM is supposed to go into power enrichment so if you are having large amounts of knock on full throttle launches through the gears, it won't be TC clutch related. Check timing also and make sure it hasn't been advanced. Mine was advanced 8 degrees by previous owner. Runs soooo much cooler when it is set where it is supposed to be :roll:
HTH,
Blake