I have a 1999 Chrysler 300M that's been having problems and has gotten worse.

First off, the engine at idle runs abit wild. It'll go from 600RPM to about 2000RPM. I let it sit one day to see how high it will go on the RPMs and I let it get to about 3500 and I shut it off. It gradually got up that high and was continuing if I didn't stop it.

Secondly, While driving the RPMs will go up and down and the car will shift hard up and down. Sometimes it won't shift at all and just be stuck, it mainly does that in 1st gear. I will put it in the Manual position, so I can change the gears myself, but yet it changes on it own.

Thirdly, the lights flicker constantly but you can barely see it. You have to concentrate on the lights to really notice it. My wife found that out before I did.

Now I have been looking all over the internet for the past few days and haven't found really anything on what to do. Only thing I have found was to clean the IAC and/or change out the PCM.

I need help with this what are ya'lls thought on this?

 

Also, forgot to mention, that this is a 3.5L V6. it has 160k miles on it as well.

 

Sounds like a vacuum leak. Search over at www.300mclub.org for help with your issues. Great site dedicated to 300M's

 

I'm having the same problems as you are with my 1999 LHS 3.5L. It's an intermittent condition on mine. I've swapped out the IAC and the problem still exists. Removed and cleaned the throttle body. Still no fix. I just ordered a new Throttle Position Sensor and it should be here tomorrow. I'll let you know if it helps.

 

Sorry for the late reply but i install the new Throttle Position Sensor and the problem is gone. I've got other things going on now but the surging idle is taken care of.