Seems to be a common myth, so lets sticky a thread explaining how the TPS works. Jrichker has provided the basic TPS guideline to follow. I'll just preference it with this. Adjusting your TPS to .99999999 volts is not necessary at all. There is a general range the computer will accept as idle voltage for the TPS. This range is 0.5 - 1.1 volts. ANYTHING within this range is acceptable. If idle voltage is outside this range, a TPS code is generated by the computer. Therefore, the only adjustment really necessary is to verify the tps voltage at idle is anywhere between the above range. If this is a FORD OEM tps, it should be. Aftermarket TPS's might be different and require you to slot the holes to get it in range. If it is in range, then you are fine. No need to chase the mythical 0.99 volts that has been tossed around for years. Upon vehicle startup, the computer will take the base idle voltage, and apply 2.71v to that number as the trigger point for WOT operations. To make a long story short. If your idle TPS voltage is anywhere between 0.5V and 1.1V...you are good to go.