Disconnecting the battery clears the OBD2 computer so all of the OBD2 tests must run again. Some run constantly, some need special conditions including how much gas in the tank and when it was last filled and how many hours have elapsed since it was turned off.
Some codes force the engine to run in "open loop" mode, no computer assistance. So, the presence of a code can affect performance.

P0010 and P0011 would have cleared themselves, there is no need to disconnect the battery when replacing them.

 

Time to catch up to this saga. I changed out the spark plugs to check their condition, look for any warning signs, and they had 150,000 miles on them. They looked fine and didn't help the problem. So after thinking through how it died all of a sudden, then ran fine I started looking for an electrical issue. Was thinking about a loose ground wire on the fuel pump, a chaffed wire, loose plug, but wanted to tow it home, lift it and inspected the underside. So I started checking the easy stuff in the fuse box. The fuel pump fuse looked good. To check the fuel pump relay I noticed the rear hatch release used the same relay, so I swapped them to test and the thing fired right up. All of this time down for a bad $4 relay. Anyway, that was it and she's been running great for a couple of weeks.

 

Awesome news, enjoy the ride!