Hello everyone. I have a bit of an issue that's driving me crazy. I have been working with Ben Charles on tuning my 2017 silverado 5.3 with an lt4 supercharger. Ben is doing a great job on the tune, but i have an idle issue that i can't seem to find a solution for. The truck just wants to idle high, between 1,300rpm and 1,500rpm in park, 850rpm-900rpm in drive. When in park, i tap the gas pedal and it will drop the idle to about 1,100rpm. But then it will slowly climb back up. The truck has an LT4 throttle body. I have tried everything and it just keeps idling high and throwing a CEL. I have done the factory relearn procedure- didnt work- no change, i have tried the throttle body clean on VCM scanner- didnt work- no change, I have switched back to my L83 throttle body- didnt work- no change. I have used carb cleaner to test for vacuum leaks around the intake couplers, and around the intake manifold runners. I just want to make sure i havent missed something. Ben has tried multiple different tunes, with no change happening. Any help would be appreciated. The codes its throwing are as follows:
P0121- Throttle/Pedal position sensor A circuit range/performance
P0507- Idle air control system RPM higher than expected
P1101- Mass airflow sensor out of self test range