Sounds like a classic case of spark knock to me. It ran fine, you filled up the tank, it knocked. Seems like the gas may be a little low in octane. I would put in some 91 or 93 and see what happens. If the sound goes away, then you know it must be spark knock.

 

before the trip, hard running always resulted in knocking noise from the 1-2 and 2-3 upshift
now, in any gear, get on the throttle from moderate to WOT and you will hear the distinctive knocking noise for a good 2 seconds
ahh well, see what the dealership says

 

u guys cant even make good beer,I hear its the same with gas lol

 

well shop forman took it for a rip, said it was normal and that its even printed in the manual that spark knock may occur and is normal

Be that as it may, but if i get on the throttle each time and it knocks, that CANNOT be normal.
He said drive it for a while, and bring it back at its next oil change and he would look into it further if it continues (about 1000km away)
Hell, my volvo with a poorly tuned carb and +8 degrees of timing doesnt even knock this hard or often.

Will pulling the battery and letting the ECU reset help in this case?

 

see if you can find 104oct unleadedracing gas
if it knocks with that in there then its the engine