About a month ago or so I had my car on the dyno getting tuned and towards the end my idle went crazy. basically when i start the car it jumps to 3k then after a few mins it falls down to 2k then a few mins after that it falls to 1.5k and stays there. when i start driving every now and then it will fall to 1k but the next red light it keeps at 1.5 again. its driving me nuts! what could it be? Thanks

 

it sounds to me like the tps sensor. or passage on the bottom of the tb.