Just use carburetor cleaner spray. Clean the entire throttle body and IAC. Make it look like new.

What he ^ said.

I believe the stalling issues have been solved. I cleaned the seat for the idle air sensor and also replaced the fuel pressure regulator. Now, the car is throwing a P1134 code. Does anyone have any suggestions as to what could be causing this code?

A sluggish sensor or possible wiring.

Do you mean a possible sluggish o2 sensor? The check engine light came on this morning & has since went off this afternoon. Ran the scan tool again and the only code was the P1134 in the memory.

For Properly cleaning the IAC I made this post a few years back now.
The IAC does control the idle and often it can get sticky/carboned up! You want the inside port to be clean as well.
https://www.gmforum.com/normal-maint...800-v6-307092/

The P1134 code also refers to HO2S Transition Time Ratio.