My dad recently acquired an '06 Silverado with a blown and cammed 4.8 in it. It had some tuning issues that I have been trying to straighten out. Unfortunately, I have no idea what I'm doing
So anyway, one of the problems it had was it didn't want to idle properly. I've worked on it some after reading some of the idle tutorials, but it still hunts up and down and occasionally dies (usually during slow speed maneuvering). Tonight, I was driving and came to a stop light. The thing would drop down to about 500 RPM and then shoot up to over 1500, then fall back down and shoot up over and over. It was pretty obnoxious. When I got home, I hooked up the scan tool and did some logging. I was logging several different things, but one thing I noticed seemed a little strange. The Desired IAC position was around 75 counts, but the IAC position was showing to be 310 counts. I have logged IAC position a couple of times, and it is always exactly 310 counts and never moves. The TP % will move up and down as the idle goes up and down. Can anyone explain what the IAC is supposed to do?