TPS percent @ idle

Is your concern the high value of the TPS or are you trying to understand how it works?

The TPS sensor is NOT used the same way it was during the SPEED DENSITY strategy days. The Mass Air Flow (MAF) strategy uses the TPS mainly for closed throttle and WOT processing. Remember, the PCM already knows how much air is passing through the butterfly valve because of the MAF sensor.

The PCM needs to know when the throttle is closed so that the idle trim strategy can be enabled.

The PCM needs to know when the throttle is at WOT so that the WOT tables/strategy can be enabled.

The bottom line is that the VALUE of TPS is not as important as the stability of the value/position.

Please review the following excerpt from the Ford service CD.

Idle Speed Control Closed Throttle Determination.

One of the fundamental criteria for entering rpm control is an indication of closed throttle. Throttle mode is always calculated to the lowest learned throttle position (TP) voltage seen since engine start. This lowest learned value is called "ratch," since the software acts like a one-way ratch. The ratch value (voltage) is displayed as the TPREL PID. The ratch value is relearned after every engine start. Ratch will learn the lowest, steady TP voltage seen after the engine starts. In some cases, ratch can learn higher values of TP. The time to learn the higher values is significantly longer than the time to learn the lower values. The brakes must also be applied to learn the longer values.

All PCM functions are done using this ratch voltage, including idle speed control. The PCM goes into closed throttle mode when the TP voltage is at the ratch (TPREL PID) value. Increase in TP voltage, normally less than 0.05 volts, will put the PCM in part throttle mode. Throttle mode can be viewed by looking at the TP MODE PID. With the throttle closed, the PID must read C/T (closed throttle). Slightly corrupt values of ratch can prevent the PCM from entering closed throttle mode. An incorrect part throttle indication at idle will prevent entry into closed throttle rpm control, and could result in a high idle. Ratch can be corrupted by a throttle position sensor or circuit that "drops out" or is noisy, or by loose/worn throttle plates that close tight during a decel and spring back at a normal engine vacuum.