Chrysler Repair: rough idling at start, exhaust gas recirculation valve, side exhaust manifold

Question
1994 chrysler LHS, rough idling at start, then in about 15 seconds or so, goes away.  I changed fuel filter and added injector cleaner couple of days ago.

Answer
Hi John,
You might try a couple of things. First see if you have any fault codes stored in the computer. Use the ignition key:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light, which remains 'on', to begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat to be sure of an accurate count. The last two sets of flashes will be 5 in each in all cases because that means "end of readout". Let me know the other flash counts in order of appearance and we'll go from there.
Then, I would take a look at the exhaust gas recirculation valve which is located behind the engine near the air intake throttle valve. It is mounted in a pipe that runs between passenger side exhaust manifold and the air intake manifold. The valve is mounted horizontally and has a valve stem between its round vacuum actuator top and the body of the valve attached to the pipe, inside the flange that connects the two parts. The stem has a slot into which you can insert the tip of a flat-bladed screwdriver so as to lever the stem back and forth against spring action which should move freely and close tightly. If the stem seems to be sticky so that stem doesn't close all the way by spring action, then you can try spraying some penetrating solvent like WD-40 on the valve stem to freeup its motion.
If the valve is sticking slightly ajar it will make for a rough idle such as you describe because the mixture is too dilute. It is one of the most common causes of this symptom. So see if you can find the valve and check/lubricate the stem. To check it in motion you can rev the engine from idle to 2500 rpm and back to idle and watch to see if the valve stem moves freely in both directions to the extreme open and closed positions. It may be that the interior of the valve is cruddy so that might require that it be unbolted from the pipe where it it attached and cleaned. But chances are good it will only be a sticky stem.
Feel free to write back with the results and other questions you might have. Use the "thank/rate" tab to get back without having to wait for me to be available to take a question. There is a space for comments.
Roland