Chrysler Repair: 00 dodge neon - rough idle/no codes, emission control devices, dodge neon

Question
QUESTION: re-rough idle: the engine is a 2.0, I have found a cheeper belt tensioner from my local checkers store. it is $268. how can i check that valve you were talking about?

ANSWER: Hi Todd,
It is located at the rear end of the engine at the corner closest to the driver. Above it there is a round control device that is vacuum line-operated and with an electrical connector. The valve itself has a round vacuum operated actuator on the top and is mounted sideways to the exhaust manifold and a pipe comes out of the valve body and runs around to the front side of the engine to just below the throttle body. Once you have found the valve notice that between the valve body and the actuator there is a flange which hides a rod what connects the valve body to the actuator. That is the valve stem. The stem has a slot which allows you to put the tip of a screwdriver and then you can move the stem back and forth, against internal spring-action which closes the valve. If the stem doesn't come to a dead stop easily via the spring-action then spray some WD-40 on the stem where it enters the body and work it back and forth to free up the 'action'. Then see if the engine will idle better. If it improves but isn't back to normal then you would take the valve off and clean out the passageways, the valve head and the valve seat.
I know it was used in the '99 model year, but not in the '01 modely year. So if you don't find it then it wasn't used in the '00 model year.  I would pursue this option before getting into the belt tensioner idea.
Roland

---------- FOLLOW-UP ----------

QUESTION: so is this attached to the firewall or the engine?

Answer
It is all attached to the engine. If you don't find it, then it may have been phased out in the '00 model year. The shop where you have it serviced should be able to ID it if there is one there. Also, check the sticker on the underside of the hood which shows all the emission control devices and their connect lines. If there is shown an "egr valve" then you have one, otherwise not.