Chrysler Repair: 93 Dodge Spirit, dodge spirit, vertical rod

Question
My Mother has a 93 Spirit that was given to her.However it idles extremely rough,I've changed the plugs and wires,looked for any vaccuum leaks but didn't find any.I'm not very familiar with this car and just trying to help her out.I did notice quite a lot of slack in the throttle cable,even though this shouldn't be the cause for the idling.What would be the most likely suspect in your opinion?..

Answer
Hi Vance,
Before I forget, if you write back tell me which engine is in the car.
One of the most common reasons for poor idling is the EGR valve being stuck open. It is found between the exhaust and the intake manifold and it has a mushroom-shaped cage on the top inside of which is a vertical rod that should move up and down when you rev the engine manually. There is a slot on the stem that will help you to see whether it is moving, and also you can use a scredriver tip in the slot to manually try and raise of lower the stem to see if it is free to move. The stem should be all the way down when you are idling because that is the postion of closed valve.
If it seems to be sticky, you can spray some lubricant on the base of the stem and see if that frees up its motion.
Other than checking that EGR valve for normal motion 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 size engine is in the car.
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.
Then write back with the results of you readout and also whether the EGR valve was stuck open.
Roland