Your post now has me wondering. I was just thinking on a performance engine, BUT now that you mention it causing a knock, my truck has been knocking pretty bad lately (last 5k miles) BUT wont knock in 1-3 and in 4th it wont knock until ~70, in 5th it wont knock until I go up big hills at highway speeds (and give ~ 1/2 throttle to get up the hill), or go into a strong wind, or go above 65.
Originally thought it might be some water in the gas (as I has siphoned about 25 gallons out of the boat which had been sitting for a month). But 10 tankfuls later (all speedway gas, just like what I have run from day 1, not to bring up the gas debate, but call this a constant) it is still knocking.
Had the timing belt done (120k miles, didnt know if it had been done before, good idea either way), thought that was it, it wasnt. So how would you check if the EGR is sticking?