techs, help!! pinging, spark knock

[mopower440]

I got a 1999 chevy silverado extended cab 4x4, has the small v-8, 4.8 liter. It wants to ping (detonate) when going wide open throttle. I have installed a new fuel pump, fuel filter, plugs and wires. We hooked up a tech2 at work and looked at the fuel trim with it running and the tech said they looked good. Then we drove it with tech2 hooked up, i nailed the throttle and he watched the tech2 and it did indeed retard the timing, so apparently the knock sensors are working.I did a carbon cleaning on it yesterday but it still pings at wide open throttle. It does a little better with premium gas but still get some pinging. Has no mods at all. Not setting codes either.