Chrysler Repair: Engine stutters at idle: 3.5L Chrysler 1999 300m, exhaust gas recirculation valve, side exhaust manifold

Question
Today my check engine light came on when I started my car and my engine shuttered for a while at idle, like it had a heart beat.  I took it to auto zone and the computer said mis-fire of multiple cylinders 4 & 5, the workers said most likely plugs or wires were the issue.  I had a COMPLETE tune up 3 months ago new plugs, wires, clean fuel system, new fuel filter, and air filter.  I also had my oil changed 1 week ago.  I'm not sure what to do

Answer
Hi Blake,
While the problem could be related to the spark system or other electronics/mechanicals of the engine, I would suggest that we look at one part that adversely affects the air/fuel ratio and results in rough idle, but without setting a specific code for itself. 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 free-up its motion.
If the valve is sticking slightly ajar it will make for a rough idle and poor acceleration 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. There is a long list of other causes of missing, but none of them are as straightforward as checking the egr so that is why I always suggest that be the first priority.
Roland