Did you put a new optical sensor in? The proper adjustment is to have about 6-11 mm3 of fuel delivery at idle, you need a bi-directional scanner to read this.
I think you are refering to the optical bump. after removing the cover on the IP you will see the sensor. T40 torx i think it is. You want to move the plate 1mm towards the passenger side of the truck. If it runs harsh and smoky you went too far. You want to be just slightly advanced for the power gains. The engine will have a little more clatter.