QuestionQUESTION: Sometimes when I am at a red traffic light my car's RPM (IDLE) will move from the normal idle to below the normal the car will start shaking as if it will cut off but will go back to the normal idle and be ok but sometimes it will cut off it will crank right back up with no problems but something is wrong and no one knows what it is b/c of course when i take it for repairs it doesn't do it
ANSWER: Hi Bessie,
I am not sure which engine is in your late model Sebring, but if it is the 2.5L V-6 my suspicion is that a smog control device called an exhaust gas recirculation valve is failing to close all the way when you are decelerating and coming to a stop. That valve is supposed to be closed at that point and also when you accelerate hard (which I no you don't do) and be open at intermediate pedal positions. You can check it yourself if that is the engine that you have. It is easy to service with a spray can of penetrating lubricant like WD-40. If you had it at the garage and they tested for fault codes and found none, then this is my suggestion for the most likely cause.
The egr valve is located along a pipe that runs from the left exhaust manifold (on the side of the engine facing the front of the car) to the intake manifold area (where the incoming air in the large rubber tube enters the throttle). That valve is metal and has a round fitting with a vacuum hose attached, mounted on the top of the valve, and the round part is attached to the main body of the valve by a sort of saddle. Inside the open saddle you will see a metal rod (with a slot) that connects the round top fitting to to the valve body. That rod is a stem on the valve and it is supposed to go in and out in response to the engine vacuum which varies with RPM and throttle opening (gas pedal position). Take a spray can of WD-40 or other penetrating lubricant and spray the stem where it enters the valve body and then use a regular screwdriver blade tip inserted in the slot to lever the valve in and out to try and free up its motion. Also check all the rubber vacuum hoses associated with the valve and a nearby vacuum solenoid valve. If the valve seems to open (against the action of a spring) and close firmly by the spring action when using the screwdriver blade to facilitate the motion, then you should be able to now start the engine. You can, once it is idling, check that the valve stem moves when you rev the engine from idle to 2500 rpm and back to idle.
Good luck on this simple repair.
Roland
---------- FOLLOW-UP ----------
QUESTION: my car is a 4 cyl does the answer you gave me still apply?
AnswerYes it does, but the location is different. If you stand on the driver's side of the hood opening and look behind the dipstick for the transmission fluid, to the right of it yu should see a fairly small horizontal pipe that comes from the place where the air intake to the engine comes (the throttle body, where you will see movement around when a helper steps on the gas pedal ,below the large air intake hose) and runs directly to the egr valve which has a flange with a couple of bolts that attach it to that pipe. The stem is horizontal, under the round top.
So look for that location.
Roland
