I have only noticed the knocking sound thus far when the truck has warmed up to operating temp.
I have actually had a few friends point out the knocking sound as they were able to hear the knocking when I was pulling up the street and slowing to enter into their driveway.
It is kind of embarassing!
I have not noticed any reduction in power or response since the knocking has started.
The only parts on the vehicle that have changed in the last few months would be the addition of a K&N air filter and modding the air intake at the fender well to a true 3 inch inner diameter.
I disconnected the battery for 1 hour while modding the air intake to reset the air/fuel mixture.
The truck is alot more responsive after these mods which were done about 3 months ago.