when driving the car for 45 min a trouble code of P0121 peddle position sensor does not allow my trans to shift gears from a stand still.

when code is erased with code scanner the car drives ok. trouble code PO171 system to lean bank one. trouble code PO128 coolant temp below thermostat regulating temp. Is this the coolant sensor? can you reference codes in more detail on what else that could be the problem?

I think you hit the nail on the head, the ECT Sensor (which is different than the temp sensor for the dash gauge)

PO121 : TP Sensor Performance

The PCM supplies 5V to the TPS - Throttle Position Sensor. The TP sensor is a variable resistor that drops the voltage to about 4 volts at WOT(wide open throttle) to less than 1 volt at closed throttle. Some TP sensors are adjustable. others have a learn procedure to determine closed throttle.

PO171 Fuel Trim System Lean

In closed loop the PCM adjusts fuel delivery based on H2OS 1 readings and is indicated by long short fuel trim values. If lean the PCM will add fuel (fuel trim above 0%) if rich the PCM will reduce fuel(fuel trim below 0%)

PO128 ECT Below Thermostat Regulating Temperature

possible failed thermostat, low or empty on coolant,

Engine Coolant Temp Sensor, Poor connection/Harness/Wires, faulty PCM Connection.

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