my car threw a throttle position sensor code today. Are those hard to replace?

Nope, not at all. https://www.gmforum.com/normal-maintainence-138/throttle-position-sensor-tps-replacement-284336/

Only difference to the link Dan posted is if it'* still there, you'll get to contend with the TB to LIM bracket that NA'* have. Remove the 8mm and pry the bracket to the front of the car. The lower bolt usually cracks loose and you'll be all set.