So, I had some battery issues for the last two weeks.
It had a dead cell and would drain down since the car doesn't get driven everyday.
It would drain to the point that I would have to give it two or three tries to get it started and it would flash the DSC and light up the TC indicator like the ECU had been reset.
After the third time I had to deal with it I replaced the battery.
Now it has been driving fine and idling fine except for a completely random stumble with and occasional stall. It has gone through drive cycles without any problems but it has also stumbled and/or stalled right after start up.
It may sit and idle for 20 minutes without issue or it could stumble right off the bat. There is no pattern or any indicators to any issue.
Start up and drivablity is normal and there is no power loss.
There are no CEL's displayed. The CEL for the mid-pipe has not popped up yet since it has only been a few days/drive cycles.
The coil packs and plugs were done in January and have approximately 4000mi on them. The plug wires were done last month, about 150-200mi ago along with a Sea Foam treatment with out issue. A compression test was also done around that time with scores in the 9's.
I am going to clean the ESS and MAF tomorrow to see if that helps. Do I have to do the KAM or NVRAM resets when I clean the sensors?
Is there anything else I need to look for when under it tomorrow? Besides vacuum leaks.

 

Check your plugs to see it they are contaminated at all from the sea foam treatment.
You need to do an NVRAM reset after you clean the ESS. Before you do clean the MAF/ESS, unplug battery, depress brake pedal a few times, clean the sensors, replace, reconnect battery, then perform the NVRAM reset.

Allow 3-5 full drive cycles, and see if that resolves your issue.