2003 Silverado V6, miss above 3000rpm

2003 silverado v6 71k miles. I just bought. Seems to run fine under normal driving conditions. Once I get to 3000 rpm, I hear what sounds like a spark knock then the engine will start to cut out rapidly and the truck will buck real bad. If I let it miss like that it will throw code p0335 (knock sensor) but this code can be caused by many other things.
The distributor was replaced recently. So far I have checked that the distributor rotor was pointing at the alignment mark at tdc, Did not replace cap or rotor, but they appeared good and to have been replaced recently. I id replace plugs (ac delco iridium) and wires.
It seems to be a ignition problem. Have not checked fuel pressure.
It also has issues with the gauge cluster, which I am replacing tomorrow. The tach jumps real high when the engine is cutting out. Dont know if it could be related.

Any ideas?