try adjusting the ignition timing(or getting a mechanic to do it)
try cleaning the air idle control valve
Inside the passenger side tire...
You will known when the fuel pump is working on the 1989 Dodge Dynasty because the engine will get fuel from the fuel tank. If the fuel pump is not working, the motor will be unable to idle or run.
The idle control solonoid is probably dirty. Take it off of the throtle body and clean it.
Perhaps the throttle plate is stuck - try to free with a screwdriver
Automatic idle sensor on the throttle body left side facing the engine from the front of the car.
Idle speed on a Dodge Neon is not adjustable. Idle is computer controlled with an airflow control motor on the throttle body.
The dodge neon has an optimum idle speed like any other car. The Dodge Neon's optimum idle speed at rest is between 12.9% and 13.3%.
Fast Idle could be a sign of a bad Throttle Position Sensor (TPS) or a bad Idle Air Control... I took the IAC out of my Caravan yesterday, I put a new IAC in it, and the reason I took it out yesterday was cause sometimes cleaning it helped the engine run better... and I also have a 92 Dodge Spirit with the same Throttle Body set up, so I adjusted the Valve on the IAC to match what the car has, and it made the van sound soooo quiet, could barely hear it, it did Idle really high until I adjusted that simple valve, your prob might be TPS or IAC... there are digital Ohm meters to check the TPS and stuff but try adjusting the IAC, it worked for me and calmed it down but it might be more serious for you then adjusting a valve. Adjusting it could be something to do since it wont cost you a thing before you go spending money on a TPS, IAC or anything else. Or was you asking how to make the vehicle idle faster?
"How do you move the idle tensioner for a 1998 3 litre dodge?"
there is no "fast idle solenoid" there has'nt been a fast idle adjustment on passenger cars in over 20 years