Expert: Roland Finston - 12/20/2011

Question
My 1999 Chrysler Cirrus 2.5L V6 runs good at high rpms, but at idle it runs rough, stalls and hesitates upon accelerating. Diagnostic code states multiple misfires.  I've done a complete tune up, changed the oxygen sensor, changed the distributor 3 times, changed the intake gaskets, the IAC, and TPS,  all resulting in no improvement with the vehicles performance. The only things I've not replaced are the EGR and the computer. Do you have any idea what else could be wrong with this car?

Answer
Hi Ron,
Did you check the egr valve to see is the stem is moving freely, against spring-action in one direction that closes the valve to a firm dead stop? What you describe could well be an egr which is gummed up around the stem so the spring doesn't close it tight at idle and when accelerating which is where it has to be or you will indeed get rough idle, dying when decelerating, hesitating on accelerating. Between the round vacuum-operated top piece of the valve, and the body of the valve you will see a flange which conceals the valve stem. The stem has a circumferential slot into which you can insert the tip of a flat blade screwdriver and that will allow you to move the valve stem back and forth to test the 'action'. Squirt some WD-40 on the valve stem where it enter the valve body and then exercise the stem and feel that it is getting to the full closed position under the action of the internal spring. Then see if that solves the problem.
There are a great number of possible causes for multiple missing, but let us check out the egr valve before getting into those. A faulty computer would likely set a code so I would not change that out for sure. No parts should be bought till we check the egr.
Roland
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