Chrysler Repair: 2000 neon: code 0171, throttle position sensor, coolant temp

Question
the car has been put back together after a front end crash.
the motor is reving very high and pulses up and down
i got a code reader and it says p171 what is going on.
how do i reduce idol rpm

Answer
The code means that the engine is running lean according to the oxygen sensor. The computer tries to correct it.
The following are possibilities:
fuel supply line restricted
fuel pump strainer clogged
fuel pump is weak
the oxygen sensor is inaccurate
or the signal from it is shorted to ground, or the heater for the sensor is shot, or it it simply unplugged, so check that out. It is on the exhaust manifold
the throttle position sensor could have a faulty variable resistance or a faulty supply wire/plug
the manifold absolute pressure sensor could be inaccurate/unplugged
the engine coolant temp sensor could be inaccurate/unplugged
the fuel pressure sensor could be inaccurate
the engine computer could have been damaged.
Sorry to give you such a long list of possibilites, but most of them are simply a matter of inspection/observation of the item listed.
There is probably a feedback loop where the computer tries to make up for the fault and overshoots, thus the oscillation in idle speed.
Roland