Sorry for the delay.
PID = OBDII Parameter ID (STFT and LTFT are examples of OBDII PIDs)
LTFT = Long Term Fuel Trim PID
STFT = Short Term Fuel Trim PID
To get these ever changing values, you would utilize a scan tool. I prefer scan tools that graph since many of the PIDs change so quickly, and it is often handy to look at some PIDs together.
So, here's what I suggest. Hook up your scan tool, warm up your car to operating temperature, and have all accessories off, ensuring PCM is in closed loop. Using gas pedal, rev engine to 2500rpm; write down LTFT and STFT after they steady out, 30 seconds maybe. Using gas pedal, rev engine to 1500rpm; write down LTFT and STFT after they steady out. Bring engine to idle; write down LTFT and STFT after they steady out.
Reply with your results and/or watch the following videos:
To me, this two part series explains STFT and LTFT the best and how to use them.
Secret of Engine Problem Diagnosis- Fuel Trims Pt.1
Secret of Engine Problem Diagnosis- Fuel Trims Pt.1 - YouTube
Schrodingers Box, ScannerDanner, and EricTheCarGuy on YouTube are very good resources.
Lastly, I just had an IAC issue. The easiest test is to first reproduce the idle issue in your driveway, meaning idle is wacky (too high or too low). Once in that state, with medium energy smack the IAC metal housing (NOT the connector) with the handle of a screw driver. Maybe hit it three to four times with medium energy. If your idle slowly returns to normal, it is a stuck IAC. Again, I had the same issue, I cleaned my IAC to be spotless, but it still would stick in numerous positions, which caused too high, too low, and just plain weird idles. I also verified a stuck IAC by looking at the duty cycle of the IAC with my scan tool to verify the computer was trying to counter the current weird idle state.
Sorry for the long answer, but I hope you find something I said to be helpful.