YotaTech Forums - Heavy thud while accelerating

First of all I just wanted to say 'hi' to everyone since I'm new to Yotatech. And thanks ahead of time for any advice/help you might have with my problem.

I recently had the C.E.L come on and give me a P0303 and P0300. I changed my plugs, used Denso Iridium, and my plug wires as well. I needed to do the tune up anyway so I figured that might just be it. Everything seemed to be going well afterward with the CEL going off on its own and the engine sounded like it was definitely running stronger until I got onto the highway and began accelerating on the on-ramp and began to get a hard thud beginning around 60mph on through 80mph. If I floor it, she'll run hard no problem it seems it is only during gradual acceleration that this happens and only above 50-60mph. Driving around town I have no problems what-so-ever.

Could it be the plugs because they are only single electrode??? I have also been hearing possibly my fuel injectors. I have a TRD S/C, 3.4L V6, 4wd, SR5 w/ K&N intake kit.:scared: