Chrysler Repair: Stalling below 1000 rpm, chrysler sebring lxi, vacuum leaks

Question
i have a 98 chrysler sebring lxi 2.5L with 100,000miles on it. the check engine light is on. the cars idle is real rough at 1000ppm and below. the car will stall out when i come to a stop and slow down. the rpm gauge fluctuates between 0-1000ppm when i am slowing down. above 1000ppm the car runs fine. it has been in the shop at least 5 times. the computer says it is mutilple misfires and throttle positioning sensor. the spark plugs and wire, cap and rotor, and throttle positioning sensor have been all replaced. the computer has been checked and is ok. it has been checked for vacuum leaks and nothing was found. i was reading on the web that it could be the idle air control valve. can you give me any suggestions. Thanks

Answer
Hello Donald,
It might be the idle air control motor/valve, but without a code for that (#25) that is a chancey replacement to make. You could easily do it yourself and find out, but I would look into a couple of other things first.
Begin by erasing all the existing codes. Just disconnect the negative post of the battery, having first turned "on" the headlights. Then once the battery post wire is disconnected, turn "off" the headlight switch, then wait for 5 minutes and reconnect the negative post. Then do the following, using ignition key: turn it "on-off-on-off-on" and leave it "on" (doing this quickly, no longer than 5 seconds). Then watch the 'check engine' light to begin flashing, then pause, flashing, pause, etc. Count the number of flashes before each pause and keep track of the numbers. Repeat the readout and verify the counts are correct. Then group them in pairs in the order that they came out, thus forming two digit numbers. You may notice that the pause is shorter between the digits of a given number, and longer between the numbers themselves. You should only get the number 12 (which means you disconnected the battery recently) and 55 (which means that is the end of the readout).
Then drive the car for a few miles, and re-check the codes again to see if anything new was logged.
Then send me a 'follow-up' question telling me the results of your readouts. I have the troubleshooting manual for several of the engines and we can look up the possibilities of what is wrong based upon what fault codes you show, if any. Mention which engine the car has.
There is also an essay on fault codes at the site:
http://www.allpar.com/fix/codes.html
which gives the meaning of the code numbers. But then you need to get specific info for what exactly might be the diagnostic tests or parts to replace to complete the repair.
Another common reason for failure to idle is that the exhaust gas recirculation valve is sticking slightly ajar due to a build-up of exhaust condensate crud. That valve needs to be closed when the throttle valve is closed at idle or the engine will die. So if you will look for a tube and a mushroom shaped valve connecting the exhaust manifold to the intake manifold you will have found the egr. Inside the "cage" of the mushroom-like cap on the valve you will see a round thin "stem" with a groove around it for easy visualizing movement of the stem. If you can idle the engine, then try revving the throttle valve to maybe 2,000 rpm and back to idle while watching the valve stem for movement. It should jump up and back quickly in response to the throttle revving technique. It if doesn't move or is sluggish then that would be symptom of an ajar valve. You can remove it and check for the condition of the valve if it appears to be suspicious.
Unless you get a code for the idle speed motor (25) or a new code, it appears that most of the other possibilities have been covered. But lets look at new codes and the function of the egr first. At 100,000 miles, a faulty egr is not unexpected.
Roland