From researching online, it looks like this is pointing to an issue on the coil or plug in cylinder 7. The weird thing is that at 100,000 miles, I replaced all the coils and plugs. I'm now at 104,000. Does it seem strange that this issue is coming up already? The car seemed to be sputtering at idle, then the Check engine light came on and I get restricted performance when accelerating.
Any ideas would be very welcome.

 

It could be a number of things but start by hoping the P0307 is useful. If you used proper plugs then they are unlikely to be the cause. Look closely at the plug well for damp/oil/dirt/etc. If none, swap coil with another and see if fault moves. If not, check connector/wiring. If it does, replace the coil.

Oil in the plug well is my guess...

 

Thanks - I will check it out and report back!

 

So I went ahead and replaced the ignition coil on cylinder 7, and decided to change the plug as well. Afterward, the car is running smooth again, no rough idle, no hesitation, and no restricted performance light anymore. Because of the tight squeeze and where that cylinder is located, I couldn't really see into the well to see if any oil had accumulated in there. I did put a clean rag down in there and it came out clean. I guess I'm just perplexed as to why a plug or coil would fail after only 5000 miles? Attached are pictures of the plug I removed. Does anyone see anything of interest on it?
Thanks once again for the help JagV8