Chrysler Repair: Rough Low Idle 1997 Sebring 2.5, throttle position sensor, carbon coating

Question
Hi. I have 71,000 miles on the 2.5. I replaced the air filter. Put dry gas and STP fuel injector cleaner in over last 300 miles. It used to idle @450 but it wants or will stall now while sitting in gear. Also if I let off the gas it will tach down too ZERO rpm if I don't touch the gas pedal. There was no check engine light on until after I removed the throttle body to put an ohm meter on the idle air control motor. The ohms read about 52 on pin 1-4 and 2-3. I took it off and cleaned what little black carbon film that was present. I also cleaned the throttle body which had black carbon coating but no ridges to hinder the valve operation or flapper inside the throttle body. I checked the throttle position sensor and was well within the 3.5 - 6.5k the book calls for. When opening the throttle body with the ignition switch on the resistance changed increased smoothly. When I put things back the car still run rough but now the engine light came on. It's reading the 12 (battery) then 24 then 24 then 55 (end of code reading. The 24 has to do with the throttle position sensor. I tried refastening the harness but still the same. I can't see what I could have done to change this but the car still runs rough. Anything above the 600 rpm and up will set yah back in your seat. My gas mileage is still around 23.8 on the last 2 tanks of gas. I read many of your posts and I'm going to check the EGR for sticking tomorrow. Any thoughts would be appreciated. I was careful with the removal of the throttle body and the TPS is still reading properly across 1-3 and 2-3. Thanks for your time.

Answer
Hi Art,
The egr may well be the problem.
If not, then to pursue the code 24 further you could check that the violet/white wire has 5 volts on it when the ignition is "on", and that the signal wire (orange/light blue) has continuity to pin 35 (color will be orange/dark blue at the plug) of one of the two black plugs on the powertrain controller and that the black/light blue ground wire is continuous to pin 43 of the other black plug.
The only other possibility is the idle by-pass passageway of the throttle body might be clogged, but which you no doubt cleaned when you cleaned the main throat of the body.
Roland