Chrysler Repair: 1995 chrysler cirrus rough idle, chrysler cirrus, 1995 chrysler cirrus

Question
Have a 1995 chrysler cirrus with 44,000 on it.  When engine is started warm it rough idles a little bit and acts like it wants to stall.  Doesn't do this when cold started.  Distributor, chips for distributor, and oxygen sensor were just replaced about 500 miles ago

Answer
Hi Jim,
I had a fellow with the same car ask a similar rough idle question, only his was the reverse of yours. I had him check for fault codes, and finding none I then told him how to check the temperature sensors that control the fuel mixture. Let me copy my two responses and ask that you try the same approach. Let me know if you find a relevant code and we can address that too.
"Becasue it is temperture dependent suggests that it may have to do more with the fuel supply than the spark, and that suggests mixture control which suggests temperature sensor function. But we don't need to guess because the engine controller may have detected the fault already.
The most useful thing to do would be to try to get the fault codes that may stored in the engine controller memory to readout. Try using the ignition key: turn it "on-off-on-off-on" and leave it "on" (doing this quickly, no longer than 5 seconds). By "on" I mean just the normal position when the engine is running, not the cranking position. The 'check engine'light will remain on when you leave the key in the "on" position with the engine still not running. But 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. Then send me a 'follow-up' question telling me the results of your readout. By the way, 55 will be the last number (two groups of 5 flashes each) and that is the code for "end of readout".
I have the troubleshooting manual for several engines and we can look up the possibilities of what is wrong based upon what fault codes you show. When you write back tell me what engine is in the Chrysler you are driving.
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.
So let me know what you find out.
 Hi Mike,
The no code situation presents more of a challenge. Because you said that the engine runs o.k. when it is cold, I would suggest that you check out the resistance of the coolant temperature sensor, when it is cold and after the engine warms up. The sensor on the 2.5 is located between the coolant fill tube and the air intake tube. It has an electrical connection that is removed by gently lifting the "ears" to release it from the tabs. The resistance across the contacts of the sensor should be between 7,000 and 13,000 ohms at 70F temperature of the coolant, and after the engine reaches typical operating temp of 200F it should read 700 to 1,000 ohms. If it doesn't drop to that low a value then the mixture will be too rich and might then be the cause of the miss. So try that first and see what you get. To help verify that you found the sensor, its wire connector colors are black/light blue and tan/black.
There is another temp sensor, the air intake temp sensor located on the intake manifold and it has a 2-wire connector where the wires are black/light blue and black/red. Its resistance values when the engine is cold (50 to 80F) should be 7,900 to 1,800 ohms, and when hot (180 to 200F) should be 170 to 20 ohms. So check that sensor out also.
Then let me know if either of them is off-value."
I await your findings, Jim.
Roland