Recently, I have begun to notice engine pinging in my Hyundai Sonata 2002
(~19,000 miles). The pinging has been occuring for ~1.5 months. The noise
is faint, but occurs quite regularly in the 1-2K RPM range. It did go away
when I used a tank of premium gas, but came back when I switched back to
regular.

My current plan is to take it in to Hyundai to be checked out. Any
thoughts or advice would be greatly appreciated; thanks in advance!

 

1k-2k rpm is low enough that pinging may not be abnormal under high load.
You should still have it checked. It's possible there's a knock sensor
issue or that you've built up enough carbon to reduce the combustion area.
An induction service may help. What I like to do is to get two cans of GM
top engine cleaner, one aerosol, one liquid. Spray the aerosol into the
throttle body per directions. Then, using a pressurized fuel injector
cleaner apparatus, use a mixture of 1/4 top engine cleaner and 3/4
gasoline to run through the injectors. The second half of this is a
procedure GM devised for cleaning injectors and freeing up piston rings.
This is not a diy job, you'll have to pay someone to do it.