What would cause unusually high idle airflow readings

What would cause unusually high idle airflow readings? I am working on my 08 escalade 6.2, cam, ls9 injectors and full bolt ons. I have always had high base airflow readings, tried multiple times to set it correctly and always end up around 13-14gs at 800rpm and 18-20 at 1000. I would expect to see closer to 8-10 at 800. I was jacking with it today, disabled all my adaptive, locked timing and throttle was staying locked at 18%. Got the idle at 1000rpm down to +-50 and ended up with it set at 20.75.... bumped it down to 800 and in gear I could get it +-50 at about 17 or so but could not get it to cooperate in park neutral.... no matter how much airflow I took out of it tpswould not drop below 18%. I'm wondering if my maf is somehow not reading correctly down low, or if I possibly have issues with my throttle body. ... one other thing I can note is it is impossible to maintain a specific idle by using the throttle, say for example if I wanted to hold at 1500 to help jump a car off or something it constantly over shoots in both directions. Like the throttle is lazy in moving. I know i should post a log and a tune, well I didn't save a log when I was working on it.... and the tune literally is probably useless since I have all adaptive disabled..... put my drive tune back on it for now. Just picking brains at the moment, looking for ideas.