Expert: Roland Finston - 6/30/2011

Question
Back around Easter, our 1999 Town & Country (188,000 mis. 3.8l engine) the idled started fluctuating starting to die but then at about 500rpms catches itself and revs up to 1000, 500, 1000... eventually it would die at stop signs and around corners. No engine lights or any error codes on the ODB reader. After reading the AllExperts site I took the throttle body off and thoroughly cleaned it and our problem went away until last week.

Same symptoms but I did not wait for the van to start dying at stop signs. I got some advice from a mechanic friend who said the problem sounded like an air supply issue. I then pulled out the idle air valve and tested it with an ohm meter and it tested faulty. (throttle position sensor tested good) Replaced the IAV and for the week the van has run well.

Tonight my idle die/rev issue is back. I do not want to continue replacing parts, can you direct me to what I should test next?

Answer
Hi Curt,
My advice would be to check the egr valve stem's action: is should move freely, against spring-action in one direction which should be able to close it to a dead stop. If the stem seems sticky then spray some WD-40 on where it enter the body of the valve and work the stem back and forth to loosen the action. That valve can get crudded up and even though it seem to close it is still leaking exhaust gas into the manifold when you are decelerating which then cause the engine to die when coming to a stop. This can happen without setting a fault code. So try the WD-40 and beyond that you could remove the valve and clean the passage way/valve seat, valve face to assure that it is not the cause of this situation. Similarly check the pcv valve which can get crudded up. They are inexpensive to replace.
Roland
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Sorry for the delay in answering but I just found your question in the 'pool' to which it was referred by Kevin.