Ive been chasing this crazy idle issue for months. Heres the facts. I disassembled the tb and the FITV and saw it was loose so tightened that white ring around the plunger. My IAC valve make a high pitched sound when the key is on but the car is not running. Unplugging the electrical connectors (obviously) makes the sound stop The car's cold idle fluctuates from 1500-3k until semi warmed up and it continuallly drops, stops fluctuating until it hits 500 rpm, from there it idles at 500 for 5 mins perfect, and then at real idle temp, the tach goes from 500 and drops to a bucking stall, then back up to 500 then bucks and usually stalls. Cleaning the IAC stopped the high pitched squeal when key is on and temporarily made the car run perfect. After 1 blast around the block, the idle returned to shit, and the high pitched sound returned. Timing is dead on 16 deg. Using chipped ecu and 403 cams. Valves adjusted recently. Cams at stock position Replaced TB and intake manifold gaskets. Checked vacuum lines. Problem has been intermittent before and after the mods, and now it just wont idle at all. I read all the idle articles. I tried all the tricks. Any shed some insight??